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    cast

    1.1.0 • Public • Published

    TL;DR

    Node

    npm install cast

    Ender

    ender add cast

    Usage

    var cast = require('cast');
    
    cast('false', 'boolean'); // will return the boolean false
    

    Intro

    Types in JavaScript can be unpredictable, and trying to protect against the edge-cases is a headache. Consider the following:

    Booleans

    true === "true" // makes sense false !== "false" // ?? false === "" // ?? true === "0" // ?? or any string

    Numbers

    isNaN(null) // false isNaN(undefined) // true

    There are many others, but these conditions make it very difficult to write truly high-level code. This module tries to solve this problem.

    The main use case is simplification of form validation/user input. A single call to cast will eliminate the need to do extensive type-checking.

    Usage

    function cast(val, type[, radix])

    • val- the value to cast (strings are the most useful, but integers and arrays can also make sense)
    • type- string or function (anything else will throw an exception)
      • if a function, an instanceof will be done internally
      • if a string, acceptable values are: 'array', 'boolean', 'float', 'integer', 'number' (alias for 'float')
    • radix- only applies for integers

    There are only two possible return values, null or something of the type specified by type. Since null cannot be assigned to (as undefined can), this makes complete sense. The first parameter is never modified, so this function truly does no evil.

    Examples

    Arrays

    cast([], 'array'); // returns cast('[]', 'array'); // returns

    Booleans

    cast('true', 'boolean'); // returns true cast('false', 'boolean'); // returns false cast(true, 'boolean'); // returns true cast(false, 'boolean'); // returns false

    Integers

    cast('10', 'integer'); // returns 10 cast('10c', 'integer'); // returns null cast('10e10', 'integer'); // returns null cast(10, 'integer'); // returns 10 cast('10', 'integer', 8); // returns 8 cast('10', 'integer', '8'); // returns 8 cast('10.1', 'integer', 10); // returns null cast('10.1', 'integer'); // returns null

    Floats

    cast('5.25', 'float'); // returns 5.25

    Strings

    cast(5, 'string'); // returns '5' cast(true, 'string'; // returns 'true' cast('hello', 'string'); // returns 'hello' cast({}, 'string'); // returns null cast(undefined, 'string'); // returns null cast(null, 'string'); // returns null cast([], 'string'); // returns null

    Keywords

    none

    Install

    npm i cast

    DownloadsWeekly Downloads

    28

    Version

    1.1.0

    License

    none

    Last publish

    Collaborators

    • amilajack