Flow Cadence Utilities API Reference

Imports

extractImports(code)

Arguments

Name	Type	Description
code	string	Cadence template code

Returns

Type	Description
object	contract name as key and import address as value

Usage

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import { extractImports } from "@onflow/flow-cadut";

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const code = `

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import Message from 0x01

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import Utilities from 0x02

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pub fun main(){

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Utilities.log(Message.hello)

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}

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`;

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const imports = extractImports(code);

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console.log(imports);

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/*

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* Line above shall show the following:

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* {

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* "Message": "0x01",

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* "Utilities": "0x02"

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* }

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* */

missingImports(code, addressMap)

Given Cadence code template and addressMap, returns an array of missing contract imports

Arguments

Name	Type	Description
code	string	Cadence template code
addressMap	AddressMap	addressMap for provided template

Returns

Type	Description
array	array strings, representing names of missing contract imports

Usage

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import { missingImports } from "@onflow/flow-cadut";

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const code = `

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import Message from 0x01

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import Utilities from 0x02

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pub fun main(){

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Utilities.log(Message.hello)

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}

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`;

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const missing = missingImports(code, {});

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console.log({ missing });

report(list, prefix)

Reports missing imports via console.error with format:

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[prefix] Missing Imports for contracts: [ Contract_1, Contract_2 ]

Arguments

Name	Type	Optional	Description
list	array		list of missing contract imports
prefix	string	✅	Default: ""

Usage

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import { missingImports, report } from "@onflow/flow-cadut";

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const code = `

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import Message from 0x01

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pub fun main(){}

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`;

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const list = missingImports(code, {});

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report(list);

reportMissingImports(code, addressMap, prefix)

Checks and reports missing contracts by matching code and addressMap in format:

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[prefix] Missing Imports for contracts: [ Contract_1, Contract_2 ]

Arguments

Name	Type	Optional	Description
code	string		Cadence template code to check
addressMap	AddressMap	✅	addressMap for imported contracts. Default: {}
prefix	string	✅	message prefix. Default: ""

Usage

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import { missingImports, report } from "@onflow/flow-cadut";

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const code = `

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import Message from 0x01

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pub fun main(){}

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`;

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reportMissingImports(code);

replaceImportAddresses(code, addressMap)

Replaces import statements in provided Cadence templates with corresponding values from addressMap

Arguments

Name	Type	Description
code	string	Cadence template code
addressMap	AddressMap	AddressMap to use map contract names to addresses

Returns

Type	Description
string	Updated template with replaced addresses

Usage

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import { replaceImportAddresses } from "@onflow/flow-cadut";

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const code = `

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import Messages from 0x01

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pub fun main(){}

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`;

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const addressMap = {

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Message: "0xf8d6e0586b0a20c7",

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};

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const replaced = replaceImportAddresses(code, addressMap);

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console.log({ replaced });

Arguments

mapArgument(type, value)

Converts provided value to sdk argument.

📣 Best usage of this method is with combination of query/mutate methods from Javascript SDK.

Arguments

Name	Type	Description
type	string	Cadence type represented as string
value	any	correspondent value to use for conversion

Returns

Type	Description
Argument	sdk argument

Usage

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import { query, config } from "@onflow/fcl";

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import { mapArgument } from "@onflow/flow-cadut";

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(async () => {

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config().put("accessNode.api", "https://rest-testnet.onflow.org");

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const cadence = `

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pub fun main(message: String): String{

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return message

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}

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`;

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// Script expects a single argument of type "String"

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const message = mapArgument("String", "Hello from Cadence!");

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// "args" shall return array of arguments.

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// We will pass "message" value into it

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const args = () => [message];

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const result = await query({ cadence, args });

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console.log(result);

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})();

mapArguments(schema, values)

Converts provided values to sdk arguments.

📣 Best usage of this method is with combination of query/mutate methods from Javascript SDK.

Arguments

Name	Type	Description
schema	array[string]	Array of Cadence types represented as string
values	array[any]	array of correspondent values to use for conversion

Returns

Type	Description
array[Argument]	array of sdk arguments

Usage

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import { query, config } from "@onflow/fcl";

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import { mapArgument } from "@onflow/flow-cadut";

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(async () => {

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config().put("accessNode.api", "https://rest-testnet.onflow.org");

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const cadence = `

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pub fun main(message: String, amount: Int): Int{

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log(message)

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return amount

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}

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`;

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// Script expects multiple arguments - "String" and "Int"

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const schema = ["String", "Int"];

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// These are the values we will convert to arguments

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const values = ["Hello from Cadence", 1337];

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// mapArguments will return an array, no extra steps are required

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const args = () => mapArguments(schema, values);

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const result = await query({ cadence, args });

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console.log(result);

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})();

mapValuesToCode(code, values)

This method will extract argument types from provided Cadence code and then converts values to corresponding types, preparing them to be passed into sdk.send

📣 Best usage of this method is with combination of query/mutate methods from Javascript SDK.

Arguments

Name	Type	Description
code	string	Cadence template code
values	array	array of values to process

Returns

Type	Description
array	array of sdk arguments

Throws

This method will throw an error if user would fail to provide required amount of arguments

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import { query, config } from "@onflow/fcl";

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import { mapValuesToCode } from "@onflow/flow-cadut";

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(async () => {

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config().put("accessNode.api", "https://rest-testnet.onflow.org");

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const cadence = `

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pub fun main(metadata: {String:String}, key: String):String {

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return metadata[key]!

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}

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`;

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const result = await query({

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cadence,

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args: () =>

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mapValuesToCode(cadence, [

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{ language: "Cadence", languageRating: "Cadence is Awesome 🤟" },

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"languageRating",

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]),

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});

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console.log(result);

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})();

Parser

getTemplateInfo(code)

Parses the code and returns TemplateInfo

Arguments

Name	Type	Description
code	string	Cadence template code to process

Usage

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import { getTemplateInfo } from "@onflow/flow-cadut";

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const script = `

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pub fun main(message:String):String{

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return 42

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}

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`;

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const info = getTemplateInfo(script);

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/*

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* "info" will contain an object:

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* {

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* type: "script",

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* args: [ 'message:String' ]

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* }

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*/

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console.log({ info });

extractSigners(code)

Parses the code and returns array of SignerPair

Arguments

Name	Type	Description
code	string	Cadence template code to process

Returns

Type	Description
SignerPair	String representation of signer pair

Usage

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import { extractSigners } from "@onflow/flow-cadut";

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const script = `

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pub fun main(){

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log("nothing to see here :)")

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}

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`;

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const signers = extractSigners(script);

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console.log({ signers });

extractScriptArguments(code)

Parses the code and returns array of ArgumentPair

Arguments

Name	Type	Description
code	string	Cadence template code to process

Returns

Type	Description
ArgumentPair	String representation of argument pair

Usage

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import { extractScriptArguments } from "@onflow/flow-cadut";

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const script = `

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pub fun main(message: String, metadata: {String:String}){

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log(message)

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}

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`;

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const args = extractScriptArguments(script);

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console.log({ args });

extractTransactionArguments(code)

Parses the code and returns array of ArgumentPair

Arguments

Name	Type	Description
code	string	Cadence template code to process

Returns

Type	Description
ArgumentPair	String representation of argument pair

Usage

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import { extractTransactionArguments } from "@onflow/flow-cadut";

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const tx = `

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transaction(message: String, metadata: {String:String}){

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prepare(signer:AuthAccount){

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}

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}

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`;

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const args = extractTransactionArguments(tx);

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console.log({ args });

extractContractName(code)

Parses the code and returns contract name

Arguments

Name	Type	Description
code	string	Cadence template code to process

Returns

Type	Description
string	name of the contract defined in template code

Usage

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import { extractContractName } from "@onflow/flow-cadut";

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const contract = `

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pub contract HelloWorld{

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init(){}

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}

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`;

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const name = extractContractName(contract);

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console.log({ name });

splitArgs(pair)

Splits ArgumentPair into array of two items

Arguments

Name	Type	Description
pair	ArgumentPair	argument pair in form of a string

Returns

Type	Description
array	first item is a name, second - string representation of type

Usage

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import { splitArgs } from "@onflow/flow-cadut";

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const simplePair = "message:String";

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const metaPair = "metadata: {String:String}";

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const simple = splitArgs(simplePair);

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const meta = splitArgs(metaPair);

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console.log({ simple, meta });

argType(pair)

Splits ArgumentPair and returns type of the argument

Arguments

Name	Type	Description
`pair	ArgumentPair	argument pair in form of a string

Returns

Type	Description
string	string representation of argument type

Usage

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import { argType } from "@onflow/flow-cadut";

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const simplePair = "message:String";

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const metaPair = "metadata: {String:String}";

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const simple = argType(simplePair);

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const meta = argType(metaPair);

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console.log({ simple, meta });

getArrayType(type)

Extracts item type from array type

Arguments

Name	Type	Description
type	string	string representation of Array type

Returns

Type	Description
string	string representation of item type

Usage

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import { getArrayType } from "@onflow/flow-cadut";

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const simpleType = getArrayType("[String]");

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const complexType = getArrayType("[{String: String}]");

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console.log({ simpleType, complexType });

getDictionaryTypes(type)

Extracts key and value types from Dictionary type

Arguments

Name	Type	Description
type	string	string representation of Dictionary type

Returns

Type	Description
array	array of strings - first item for the key type, second for the value type

Usage

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import { getDictionaryTypes } from "@onflow/flow-cadut";

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const type = "{String: UFix64}";

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const types = getDictionaryTypes(type);

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const [keyType, valueType] = types;

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console.log({ keyType, valueType });

Generator

processFolder(input, output, options)

Recursively goes through input folder and generates code for found contracts, transactions and scripts. Write files under output path.

Arguments

Name	Type	Optional	Description
input	string		path to the input folder
output	string		path to output folder
options	object	✅	additional options. Default: {}

Options

Name	Type	Optional	Description
dependency	string	✅	interactions dependency. Default: flow-cadut

Usage

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import path from "path";

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import { processFolder } from "@onflow/flow-cadut";

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(async () => {

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const input = path.resolve("./cadence");

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const output = path.resolve("./src/generated/localRegistry");

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await processFolder(input, output);

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console.log("✅ Done!");

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})();

processGitRepo(url, output, branch, options)

Fetches GitHub repository from provided url and branch. Then generates code for found contracts, transactions and scripts. Write files under output path.

Arguments

Name	Type	Optional	Description
url	string		url to GitHub repo
output	string		path to output folder
branch	string	✅	branch to use. Default: main
options	object	✅	additional options. Default: {}

Options

Name	Type	Optional	Description
dependency	string	✅	interactions dependency. Default: flow-cadut

Usage

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import path from "path";

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import { processGitRepo } from "@onflow/flow-cadut";

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(async () => {

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const url = path.resolve("https://github.com/onflow/flow-core-contracts");

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const output = path.resolve("./src/generated/localRegistry");

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await processGitRepo(url, output);

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console.log("✅ Done!");

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})();

Interactions

setEnvironment(network, options)

Sets flow.network config value

Arguments

Name	Type	Optional	Description
network	string	✅	network to use. Default: emulator
options	object	✅	extra options to adjust config

Network Variants

Variants	Description
emulator	Emulator instance running locally at "http://localhost:8080"
testnet	Testnet access node at https://access-testnet.onflow.org
mainnet	Mainnet access node at "https://access.mainnet.onflow.org"

Options

Name	Type	Optional	Description
options.port	number	✅	port for emulator. Default: 8080
options.endpoint	string	✅	Access API endpoint.

⚠️ Attention: endpoint will override port and provided network. Don't mix endpoint from different network - it might lead to unexpected result.

Usage

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import { setEnvironment } from "@onflow/flow-cadut";

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(async () => {

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await setEnvironment("testnet");

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})();

getEnvironment()

Returns a set of deployed contracts for current environment

Returns

Type	Description
object	AddressMap for known contracts deployed in current environment

Usage

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import { setEnvironment, getEnvironment } from "@onflow/flow-cadut";

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(async () => {

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await setEnvironment("mainnet");

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const addressMap = await getEnvironment();

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console.log({ addressMap });

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})();

hexContract(code)

Prepares Cadence template code to pass into deployment transaction. Syntax sugar for Buffer.from(code, "utf8").toString("hex");

Arguments

Name	Type	Description
code	string	Cadence template code

Returns

Type	Description
string	hex representation of template code

Usage

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import { hexContract } from "@onflow/flow-cadut";

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const code = `

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pub contract HelloWorld{

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init(){}

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}

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`;

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const hexed = hexContract(code);

executeScript(args)

Sends script to the network

Arguments

Name	Type	Description
args	ScriptArguments	script arguments

Returns

Type	Description
ScriptResult	Result of script execution.

ScriptArguments

Name	Type	Optional	Description
code	string		Cadence code to execute
args	arrayInteractionArgument	✅	Optional if script does not expect arguments. Default: []
addressMap	AddressMap	✅	address map to use for import replacement. Default: {}
limit	number	✅	gas limit. Default: 100

ScriptResult

Script result is represented as a tuple [result, error]

Name	Type	Description
result	any	result of script execution. Type of this value depends on script return value
error	error	Caught error. This will be null if script executed successfully

Usage

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import { executeScript } from "@onflow/flow-cadut";

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(async () => {

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const code = `

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pub fun main():Int{

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return 42

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}

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`;

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const [result, err] = executeScript({ code });

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console.log({ result });

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})();

Alias

This method is also available under alias query

sendTransaction

Sends script to the network

Arguments

Name	Type	Optional	Description
args	TransactionArguments		transaction arguments
waitForExecution	boolean	✅	wait for transaction execution or not

If waitForExecution flag is set to true, method will not return result until fcl.tx(hash).onceExecuted() is resolved

Returns

Type	Description
TransactionResult	Result of script execution.

TransactionArguments

Name	Type	Optional	Description
code	string		Cadence code to execute
payer	AuthorizationFunction		The authorization function that returns a valid AuthorizationObject for the payer role.
signers	[AuthorizationFunction]	✅	an array of AuthorizationObject representing transaction authorizers. Default: same as payer
proposer	AuthorizationFunction	✅	The authorization function that returns a valid AuthorizationObject for the proposer role. Default: same as payer
args	[Any]	✅	Optional if transactions does not expect arguments. Default: []
addressMap	AddressMap	✅	address map to use for import replacement. Default: {}
limit	number	✅	gas limit. Default: 100

When being used in the browser, you can pass built-in fcl.authz function to produce the authorization (signatures) for the current user. When calling this method from Node.js, you will need to supply your own custom authorization functions.

TransactionResult

Transaction result is represented as a tuple [result, error]

Name	Type	Description
ResponseObject	any	result of transaction execution. Type of this value depends on script return value
error	error	Caught error. This will be null if script executed successfully

Usage

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import { authenticate, currentUser, authz, config } from "@onflow/fcl";

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import { sendTransaction } from "@onflow/flow-cadut";

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config()

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.put("accessNode.api", "https://rest-testnet.onflow.org") // Configure FCL's Access Node

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.put("challenge.handshake", "https://fcl-discovery.onflow.org/testnet/authn") // Configure FCL's Wallet Discovery mechanism

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.put("0xProfile", "0xba1132bc08f82fe2"); // Will let us use `0xProfile` in our Cadence

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(async () => {

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currentUser().subscribe(async (user) => {

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const code = `

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transaction {

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prepare(currentUser: AuthAccount) {

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log("hello")

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}

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}`;

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const [result] = await sendTransaction({ code, payer: authz });

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console.log({ result });

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});

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authenticate();

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})();

Alias

This method is also available under alias mutate