safe access to deeply nested properties and functions in JS objects without getting a TypeError


Keywords
getter, get, nested, property, deep, TypeError, dot, path, access, js-objects, nested-properties
License
MIT
Install
npm install get-safe@1.5.0

Documentation

get-safe

Safe access to deeply nested properties or functions in JS objects without getting a TypeError but undefined instead.

You can even call a nested function in objects if the last nested key ends with (). You can pass arguments by adding them as last parameters of the get-safe function call.

Install:

Using npm

npm install get-safe --save

Using yarn:

yarn add navscroll

Directly include it in html:

<!-- Browsers with ES module support load this file. -->
<script type="module" src="node_modules/get-safe/browser-version/get-safe.js"></script>

<!-- Older browsers load this file (and module-supporting -->
<!-- browsers know when *not* to load this file). -->
<script nomodule src="node_modules/get-safe/browser-version/get-safe-legacy.js"></script>

Warning! The only gotcha here is Safari 10 doesn’t support the nomodule attribute, but you can solve this by inlining a JavaScript snippet in your HTML prior to using any <script nomodule> tags. (Note: this has been fixed in Safari 11).

The browser version adds the `getSafe` function to the 'window' object that you can use !

How to use

const _ = require ('get-safe');
const myObj = {
 foo: {
   bar: {
     baz: ['winter','is','coming'],
     fifo (arg1, arg2) {
       console.log("I'am a function, arguments are:",...arguments);
       return 42;
     }
   }
 }
};

// Tests
console.log(_('foo.bar.baz.2',myObj)); // logs 'coming'
console.log(_('foo.bar.fifo()',myObj,'arg1','arg2')); // calls the nested function 'fifo' and logs its result
console.log(_('foo.inexistant.property.baz',myObj)); // logs 'undefined'

NOTE: If you are NOT making a function call and just accessing a property, you can pass a default value as the third argument, this will be returned instead of undefined if the nested property doesn't exsit.