Lazy Require

Lazy require allows you to require modules lazily, meaning that when you lazy require a module that is missing, lazy require will automatically install it for you.

Usage

// Import
var lazyRequire = require('lazy-require')

// Attempt to load the module `ambi`, if it doesn't exist, then try to install it and load it again
// Do this synchronously, only available in Node 0.12 and above
// Passing a callback as the 3rd argument will do this asynchronously, available in all node versions
var ambi = lazyRequire('ambi', {
    /* options */
})
if (ambi instanceof Error) {
    // Error ....
    console.log('ambi failed to load because of:', ambi.stack)
} else {
    // Success ...
}

// Attempt to load the module `ambi`, if it doesn't exist, then try to install it and load it again
// Do this synchronously but with a callback, only available in Node 0.12 and above
lazyRequire.sync(
    'ambi',
    {
        /* options */
    },
    function (err, ambi) {
        // Error ...
        if (err)
            return console.log('ambi failed to load because of:', err.stack)

        // Success ...
    }
)

// Attempt to load the module `ambi`, if it doesn't exist, then try to install it and load it again
// Do this asynchronously, available in all node versions
lazyRequire.async(
    'ambi',
    {
        /* options */
    },
    function (err, ambi) {
        // Error ...
        if (err)
            return console.log('ambi failed to load because of:', err.stack)

        // Success ...
    }
)

// Attempt to load the module `ambi`, if it doesn't exist, then try to install it and load it again
// Do this synchronously if supported (Node 0.12 and above), otherwise do it asynchronously
lazyRequire.auto(
    'ambi',
    {
        /* options */
    },
    function (err, ambi) {
        // Error ...
        if (err)
            return console.log('ambi failed to load because of:', err.stack)

        // Success ...
    }
)

The following options are supported:

cwd the module path that you would like the requested package to be installed to if it doesn't exist, always recommended
save if the requested package doesn't exist, would you like to do a npm --save for it to add it to your cwd's package.json dependencies?

There's some other methods also available to you, for now, read the source to discover them.

Install

npm

Install: npm install --save lazy-require
Import: import * as pkg from ('lazy-require')
Require: const pkg = require('lazy-require')

jspm

<script type="module">
    import * as pkg from '//dev.jspm.io/lazy-require@4.6.0'
</script>

Editions

This package is published with the following editions:

lazy-require aliases lazy-require/source/index.js
lazy-require/source/index.js is ESNext source code for Node.js with Require for modules
lazy-require/edition-browsers/index.js is ESNext compiled for web browsers with Require for modules