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    0.0.4 • Public • Published

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    Assert-style non-intrusive type checks.


    It works similar to assert() where you simply state what should happen and then continue to operate. If the type check fails, a valid TypeError is thrown and your function will halt.

    Simple example:

    function add (a, b) {
      typeCheck('number', a)
      typeCheck('number', b)
      return a + b
    add(1, 1) // returns 2
    add('1', 1) // throws TypeError
    add('1') // throws TypeError
    add(1) // throws TypeError
    // etc.

    Available Types

    Type detection is handled by type-detect by the lovely team over at chaijs. If you would like to use your own type detection, you can swap it out by replacing the function at typeCheck.typeOf:

    const typeCheck = require('@karimsa/type-check')
    // this replaces the type-detect typeOf function with just a native
    // use of typeof (which is faster but less useful)
    typeCheck.typeOf = function (value) {
      return typeof value

    If you would like to make types optional (i.e. the type, undefined, or null) - just append ? to the end of the type name.

    Example with optional types:

    // all valid
    typeCheck('number?', 2)
    typeCheck('number?', undefined)
    typeCheck('number?', null)
    // invalid
    typeCheck('number?', '2')


    Licensed under MIT license.

    Copyright © 2018-present Foko Inc. All rights reserved.


    npm i @foko/type-check

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