181 lines
5.4 KiB
Markdown
181 lines
5.4 KiB
Markdown
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object-path
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===========
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Access deep properties using a path
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[](http://badge.fury.io/js/object-path)
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[](https://travis-ci.org/mariocasciaro/object-path)
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[](https://coveralls.io/r/mariocasciaro/object-path)
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[](https://david-dm.org/mariocasciaro/object-path#info=devDependencies)
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## Changelog
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### 0.11.0
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* Introduce ability to specify options and create new instances of `object-path`
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* Introduce option to control the way `object-path` deals with inherited properties (`includeInheritedProps`)
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* New default `object-path` instance already configured to handle not-own object properties (`withInheritedProps`)
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### 0.10.0
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* Improved performance of `get`, `set`, and `push` by 2x-3x
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* Introduced a benchmarking test suite
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* **BREAKING CHANGE**: `del`, `empty`, `set` will not affect not-own object's properties (made them consistent with the other methods)
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## Install
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### Node.js
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```
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npm install object-path --save
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```
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### Bower
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```
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bower install object-path --save
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```
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### Typescript typings
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```
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typings install --save dt~object-path
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```
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## Usage
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```javascript
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var obj = {
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a: {
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b: "d",
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c: ["e", "f"],
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'\u1200': 'unicode key',
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'dot.dot': 'key'
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}
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};
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var objectPath = require("object-path");
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//get deep property
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objectPath.get(obj, "a.b"); //returns "d"
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objectPath.get(obj, ["a", "dot.dot"]); //returns "key"
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objectPath.get(obj, 'a.\u1200'); //returns "unicode key"
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//get the first non-undefined value
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objectPath.coalesce(obj, ['a.z', 'a.d', ['a','b']], 'default');
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//empty a given path (but do not delete it) depending on their type,so it retains reference to objects and arrays.
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//functions that are not inherited from prototype are set to null.
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//object instances are considered objects and just own property names are deleted
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objectPath.empty(obj, 'a.b'); // obj.a.b is now ''
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objectPath.empty(obj, 'a.c'); // obj.a.c is now []
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objectPath.empty(obj, 'a'); // obj.a is now {}
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//works also with arrays
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objectPath.get(obj, "a.c.1"); //returns "f"
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objectPath.get(obj, ["a","c","1"]); //returns "f"
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//can return a default value with get
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objectPath.get(obj, ["a.c.b"], "DEFAULT"); //returns "DEFAULT", since a.c.b path doesn't exists, if omitted, returns undefined
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//set
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objectPath.set(obj, "a.h", "m"); // or objectPath.set(obj, ["a","h"], "m");
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objectPath.get(obj, "a.h"); //returns "m"
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//set will create intermediate object/arrays
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objectPath.set(obj, "a.j.0.f", "m");
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//will insert values in array
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objectPath.insert(obj, "a.c", "m", 1); // obj.a.c = ["e", "m", "f"]
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//push into arrays (and create intermediate objects/arrays)
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objectPath.push(obj, "a.k", "o");
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//ensure a path exists (if it doesn't, set the default value you provide)
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objectPath.ensureExists(obj, "a.k.1", "DEFAULT");
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var oldVal = objectPath.ensureExists(obj, "a.b", "DEFAULT"); // oldval === "d"
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//deletes a path
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objectPath.del(obj, "a.b"); // obj.a.b is now undefined
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objectPath.del(obj, ["a","c",0]); // obj.a.c is now ['f']
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//tests path existence
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objectPath.has(obj, "a.b"); // true
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objectPath.has(obj, ["a","d"]); // false
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//bind object
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var model = objectPath({
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a: {
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b: "d",
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c: ["e", "f"]
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}
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});
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//now any method from above is supported directly w/o passing an object
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model.get("a.b"); //returns "d"
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model.get(["a.c.b"], "DEFAULT"); //returns "DEFAULT"
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model.del("a.b"); // obj.a.b is now undefined
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model.has("a.b"); // false
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```
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### How `object-path` deals with inherited properties
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By default `object-path` will only access an object's own properties. Look at the following example:
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```javascript
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var proto = {
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notOwn: {prop: 'a'}
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}
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var obj = Object.create(proto);
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//This will return undefined (or the default value you specified), because notOwn is
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//an inherited property
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objectPath.get(obj, 'notOwn.prop');
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//This will set the property on the obj instance and not the prototype.
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//In other words proto.notOwn.prop === 'a' and obj.notOwn.prop === 'b'
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objectPath.set(obj, 'notOwn.prop', 'b');
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```
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To configure `object-path` to also deal with inherited properties, you need to create a new instance and specify
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the `includeInheritedProps = true` in the options object:
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```javascript
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var objectPath = require("object-path");
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var objectPathWithInheritedProps = objectPath.create({includeInheritedProps: true})
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```
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Alternatively, `object-path` exposes an instance already configured to handle inherited properties (`objectPath.withInheritedProps`):
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```javascript
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var objectPath = require("object-path");
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var objectPathWithInheritedProps = objectPath.withInheritedProps
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```
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Once you have the new instance, you can access inherited properties as you access other properties:
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```javascript
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var proto = {
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notOwn: {prop: 'a'}
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}
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var obj = Object.create(proto);
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//This will return 'a'
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objectPath.withInheritedProps.get(obj, 'notOwn.prop');
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//This will set proto.notOwn.prop to 'b'
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objectPath.set(obj, 'notOwn.prop', 'b');
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```
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### Immutability
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If you are looking for an *immutable* alternative of this library, you can take a look at: [object-path-immutable](https://github.com/mariocasciaro/object-path-immutable)
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### Credits
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* [Mario Casciaro](https://github.com/mariocasciaro) - Author
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* [Paulo Cesar](https://github.com/pocesar) - Major contributor
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