A tiny JavaScript utility to access deep properties using a path (for Node and the Browser)
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README.md

object-path

Access deep properties using a path

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Changelog

0.11.0

  • Introduce ability to specify options and create new instances of object-path
  • Introduce option to control the way object-path deals with inherited properties (includeInheritedProps)
  • New default object-path instance already configured to handle not-own object properties (withInheritedProps)

0.10.0

  • Improved performance of get, set, and push by 2x-3x
  • Introduced a benchmarking test suite
  • BREAKING CHANGE: del, empty, set will not affect not-own object's properties (made them consistent with the other methods)

Install

Node.js

npm install object-path --save

Bower

bower install object-path --save

Typescript typings

typings install --save dt~object-path

Usage

var obj = {
  a: {
    b: "d",
    c: ["e", "f"],
    '\u1200': 'unicode key',
    'dot.dot': 'key'
  }
};

var objectPath = require("object-path");

//get deep property
objectPath.get(obj, "a.b");  //returns "d"
objectPath.get(obj, ["a", "dot.dot"]);  //returns "key"
objectPath.get(obj, 'a.\u1200');  //returns "unicode key"

//get the first non-undefined value
objectPath.coalesce(obj, ['a.z', 'a.d', ['a','b']], 'default');

//empty a given path (but do not delete it) depending on their type,so it retains reference to objects and arrays.
//functions that are not inherited from prototype are set to null.
//object instances are considered objects and just own property names are deleted
objectPath.empty(obj, 'a.b'); // obj.a.b is now ''
objectPath.empty(obj, 'a.c'); // obj.a.c is now []
objectPath.empty(obj, 'a'); // obj.a is now {}

//works also with arrays
objectPath.get(obj, "a.c.1");  //returns "f"
objectPath.get(obj, ["a","c","1"]);  //returns "f"

//can return a default value with get
objectPath.get(obj, ["a.c.b"], "DEFAULT");  //returns "DEFAULT", since a.c.b path doesn't exists, if omitted, returns undefined

//set
objectPath.set(obj, "a.h", "m"); // or objectPath.set(obj, ["a","h"], "m");
objectPath.get(obj, "a.h");  //returns "m"

//set will create intermediate object/arrays
objectPath.set(obj, "a.j.0.f", "m");

//will insert values in array
objectPath.insert(obj, "a.c", "m", 1); // obj.a.c = ["e", "m", "f"]

//push into arrays (and create intermediate objects/arrays)
objectPath.push(obj, "a.k", "o");

//ensure a path exists (if it doesn't, set the default value you provide)
objectPath.ensureExists(obj, "a.k.1", "DEFAULT");
var oldVal = objectPath.ensureExists(obj, "a.b", "DEFAULT"); // oldval === "d"

//deletes a path
objectPath.del(obj, "a.b"); // obj.a.b is now undefined
objectPath.del(obj, ["a","c",0]); // obj.a.c is now ['f']

//tests path existence
objectPath.has(obj, "a.b"); // true
objectPath.has(obj, ["a","d"]); // false

//bind object
var model = objectPath({
  a: {
    b: "d",
    c: ["e", "f"]
  }
});

//now any method from above is supported directly w/o passing an object
model.get("a.b");  //returns "d"
model.get(["a.c.b"], "DEFAULT");  //returns "DEFAULT"
model.del("a.b"); // obj.a.b is now undefined
model.has("a.b"); // false

How object-path deals with inherited properties

By default object-path will only access an object's own properties. Look at the following example:

var proto = {
  notOwn: {prop: 'a'}
}
var obj = Object.create(proto);

//This will return undefined (or the default value you specified), because notOwn is
//an inherited property
objectPath.get(obj, 'notOwn.prop');

//This will set the property on the obj instance and not the prototype.
//In other words proto.notOwn.prop === 'a' and obj.notOwn.prop === 'b'
objectPath.set(obj, 'notOwn.prop', 'b');

To configure object-path to also deal with inherited properties, you need to create a new instance and specify the includeInheritedProps = true in the options object:

var objectPath = require("object-path");
var objectPathWithInheritedProps = objectPath.create({includeInheritedProps: true})

Alternatively, object-path exposes an instance already configured to handle inherited properties (objectPath.withInheritedProps):

var objectPath = require("object-path");
var objectPathWithInheritedProps = objectPath.withInheritedProps

Once you have the new instance, you can access inherited properties as you access other properties:

var proto = {
  notOwn: {prop: 'a'}
}
var obj = Object.create(proto);

//This will return 'a'
objectPath.withInheritedProps.get(obj, 'notOwn.prop');

//This will set proto.notOwn.prop to 'b'
objectPath.set(obj, 'notOwn.prop', 'b');

Immutability

If you are looking for an immutable alternative of this library, you can take a look at: object-path-immutable

Credits