Go Functions

Utility functions for functions.

• version: 1.0.0
• license: GNU LGPLv3

Installation

npm i go-fns

or

yarn add go-fns

Usage

ES6

import { not } from 'go-fns'

[1, 2, 3.1].filter(not(Number.isInteger)); // => [3.1]

Node

const { not } = require('go-fns');

[1, 2, 3.1].filter(not(Number.isInteger)); // => [3.1]

Web browser

<script src="dist/go-fns.min.js"></script>
<script>
    const { not } = Functions;

	[1, 2, 3.1].filter(not(Number.isInteger)); // => [3.1]
</script>

Documentation

Table of Contents

• Utility
  • pipe
    • Parameters
    • Examples
  • spread
    • Parameters
    • Examples
  • attempt
    • Parameters
    • Examples
  • repeat
    • Parameters
    • Examples
  • delay
    • Parameters
    • Examples
• Logic
  • and
    • Parameters
    • Examples
  • or
    • Parameters
    • Examples
  • xor
    • Parameters
    • Examples
  • nor
    • Parameters
    • Examples
  • not
    • Parameters
    • Examples

Utility

pipe

Creates a function that executes a series of functions in the order provided. First it passes the parameters to the first function and then the output is used as the input for the next function in the sequence, and so on until it reaches the end and finally it returns the output of the last function.

Parameters

• fns ...Function The functions to execute sequentially.

Examples

pipe(Math.floor)(4.5); // => 4

pipe(Math.floor, Math.sqrt)(4.5); // => 2

• Throws TypeError if any of the given values is not a function, null or undefined.

Returns Function The new function that sequentially executes the given functions.

Meta

• since: 1.0.0

spread

• See: Spread operator
• See: Function.prototype.apply

Creates a function that takes an array of values and passes the values to the given function as individual parameters.

Parameters

• fn Function The function to execute with individual parameters.

Examples

function sum(a, b) {
   return a + b;
}

spread(sum)([1, 2]); // => 3

• Throws TypeError if fn is not a function.

Returns Function The new function that passes an array of values to the given function as individual parameters.

Meta

• since: 1.0.0

attempt

Attempts to execute a function and returns the result or if there was an error, the error object caught.

Parameters

• fn Function The function to attempt.
• args ...any? The arguments for the function.

Examples

attempt(JSON.parse, "1"); // => 1

attempt(JSON.parse, ""); // => SyntaxError

• Throws TypeError if fn is not a function.

Returns (any | Error) The result of executing the function or the error object caught if there was an error.

Meta

• since: 1.0.0

repeat

Executes a function for a specified number of times and returns the results in a new array.

Parameters

• fn Function The function to execute.
• count number The number of times to execute. (optional, default 0)
• args ...any? The arguments for the function.

Examples

repeat(Math.floor, 3, 1.5); // => [1, 1, 1]

• Throws TypeError if fn is not a function.

Returns Array The new array containing the results.

Meta

• since: 1.0.0

delay

• See: setTimeout

Executes a function after a specified number of milliseconds with the arguments provided.

Parameters

• fn Function The function to execute after a delay.
• delay number The number of milliseconds to wait before executing the function. (optional, default 0)
• args ...any? The arguments for the function.

Examples

delay(log, 1000, "hi"); // => prints "hi" after 1 second.

• Throws TypeError if fn is not a function.

Returns number The timer id.

Meta

• since: 1.0.0

Logic

Propositional logic connectives

and

Creates a function that tests if all the given functions return a truthy value. The parameters you pass when invoking the created function will be passed down to the given functions with the this binding of the respective function.

Parameters

• fns ...Function The functions to test.

Examples

and(isString, isPrimitive)("abc"); // => true

and(isString, isPrimitive)(new String("abc")); // => false

• Throws TypeError if any of the given values is not a function, null or undefined.

Returns Function The new function that tests if all the given functions return a truthy value.

Meta

• since: 1.0.0

or

Creates a function that tests if any of the given functions return a truthy value. The parameters you pass when invoking the created function will be passed down to the given functions with the this binding of the respective function.

Parameters

• fns ...Function The functions to test.

Examples

or(isString, isNumber)("abc"); // => true

or(isString, isNumber)(true); // => false

• Throws TypeError if any of the given values is not a function, null or undefined.

Returns Function The new function that tests if any of the functions return a truthy value.

Meta

• since: 1.0.0

xor

Creates a function that tests if exactly one of the given functions returns a truthy value. The parameters you pass when invoking the created function will be passed down to the given functions with the this binding of the respective function.

Parameters

• fns ...Function The functions to test.

Examples

xor(isString, isNumber)("abc"); // => true

xor(isString, isNumber)(1);  // => true

xor(isString, isNumber)(true); // => false

• Throws TypeError if any of the given values is not a function, null or undefined.

Returns Function The new function that tests if exactly one of the given functions return a truthy value.

Meta

• since: 1.0.0

nor

Creates a function that tests if all the given functions return a falsy value. The parameters you pass when invoking the created function will be passed down to the given functions with the this binding of the respective function.

Parameters

• fns ...Function The functions to test.

Examples

nor(isString, isNumber)(true); // => true

nor(isString, isNumber)("abc"); // => false

• Throws TypeError if any of the given values is not a function, null or undefined.

Returns Function The new function that tests if all the given functions return a falsy value.

Meta

• since: 1.0.0

not

Creates a function that negates the result of the given function. The parameters you pass when invoking the created function will be passed down to the given function with the this binding of the given function.

Parameters

• fn Function The function to negate.

Examples

not(isString)(1); // => true

not(isString)("abc"); // => false

• Throws TypeError if the given value is not a function.

Returns Function The new function that negates the result of the given function.

Meta

• since: 1.0.0