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    invariant
    DefinitelyTyped icon, indicating that this package has TypeScript declarations provided by the separate @types/invariant package

    2.2.4 • Public • Published

    invariant

    Build Status

    A mirror of Facebook's invariant (e.g. React, flux).

    A way to provide descriptive errors in development but generic errors in production.

    Install

    With npm do:

    npm install invariant

    invariant(condition, message)

    var invariant = require('invariant');
     
    invariant(someTruthyVal, 'This will not throw');
    // No errors
     
    invariant(someFalseyVal, 'This will throw an error with this message');
    // Error: Invariant Violation: This will throw an error with this message

    Note: When process.env.NODE_ENV is not production, the message is required. If omitted, invariant will throw regardless of the truthiness of the condition. When process.env.NODE_ENV is production, the message is optional – so they can be minified away.

    Browser

    When used with browserify, it'll use browser.js (instead of invariant.js) and the envify transform will inline the value of process.env.NODE_ENV.

    Node

    The node version is optimized around the performance implications of accessing process.env. The value of process.env.NODE_ENV is cached, and repeatedly used instead of reading process.env. See Server rendering is slower with npm react #812

    Install

    npm i invariant

    DownloadsWeekly Downloads

    13,139,274

    Version

    2.2.4

    License

    MIT

    Unpacked Size

    7.64 kB

    Total Files

    7

    Last publish

    Collaborators

    • zertosh
    • cpojer
    • yungsters