composite-object

A module for mapping between multi-part string keys and values

Install

npm install composite-object

Usage

const { CompositeObject } = require("composite-object");
const map = new CompositeObject();
map.set(["a", "b", "c"], "test-value");
map.get(["a", "b", "c"]);
//=> 'test-value'

API

new CompositeObject([entries, [options]])

entries

Type: CompositeObject Object

Properties to populate the CompositeObject with. Object inputs must be in the same form as those created by the CompositeObject.prototype.toJSON() method.

const compositeObject1 = new CompositeObject();
const compositeObject2 = new CompositeObject(compositeObject1);
const compositeObject3 = new CompositeObject({ a: "test-value", b: "test-value-2" }, { keyLength: 1 });
const compositeObject4 = new CompositeObject({ a: { b: "test-value" } }, { keyLength: 2 });
const compositeObject4 = new CompositeObject({ a: { b: { c: "test-value" } } }, { keyLength: 3 });

options

Type: Object

copy

Type: "reference" "on-write" "keys"
Default: "keys"

Determines when the keys for the provided CompositeObject or Object are copied.

"reference"

Never copy keys. Changes made will affect the source. Only supported for copying an Object.

"on-write"

Copy keys as changes are made.

"keys"

Copy all keys immediately.

keyLength

Type: number

Manually specify the length of keys. Only used when constructing using an Object.

CompositeObject.prototype.clear()

Removes all key/value pairs from the CompositeObject.

CompositeObject.prototype.delete(key)

Returns true if a property in the CompositeObject existed and has been removed, or false if the property does not exist.

key

Type: string[]

The key of the property to be deleted. Shorter keys will delete all properties with matching keys.

CompositeObject.prototype.entries()

Returns a new Iterator object that contains an array of [key, value] for each property in the CompositeObject.

CompositeObject.prototype.forEach(callbackFn)

Calls callbackFn once for each property present in the CompositeObject.

CompositeObject.prototype.get(key)

Returns the value associated to the key, or undefined if there is none.

key

Type: string[]

The key of the property to be returned. Shorter keys will return the Object associated to the key if one exists.

CompositeObject.prototype.has(key)

Returns a boolean asserting whether a value has been associated to the key in the CompositeObject or not.

key

Type: string[]

The key of the property to be found. Shorter keys will find any properties with matching keys.

CompositeObject.prototype.keys()

Returns a new Iterator object that contains the keys for each property in the CompositeObject.

CompositeObject.prototype.set(key, value)

Sets the value of the key in the CompositeObject. Returns the CompositeObject.

key

Type: string[]

The key to set the value for. All keys must have the same Array length.

value

Type: any

The value to store.

CompositeObject.prototype.toJSON()

Returns a tree-like Object structure containing all properties in the CompositeObject.

const compositeObject = new CompositeObject();
compositeObject.set(["a", "b", "c"], "test-value");
const json = JSON.stringify(compositeObject);
console.log(json);
//=>{ "a": { "b": { "c": "test-value" } } }
const compositeObject2 = new CompositeObject(JSON.parse(json), { keyLength: 3 });

CompositeObject.prototype.values()

Returns a new Iterator object that contains the values for each property in the CompositeObject.

CompositeObject.prototype[@@iterator]()

Returns a new Iterator object that contains an array of [key, value] for each property in the CompositeObject.

TypeScript

To provide better typing support, you can import copies of the CompositeObject class typed for the length of key being used.

import { CompositeObject3 } from "composite-object";
enum StringEnum {
    One = "one",
    Two = "two",
}
const compositeObject = new CompositeObject3<string, "a" | "b", MyStringEnum, string>();
compositeObject.set(["key-part", "a", MyStringEnum.One], "test-value");
const value: string = compositeObject.get(["key-part", "a", MyStringEnum.One]);
const subObject: Record<MyStringEnum, string> = compositeObject.get(["key-part", "a"]);

Related

• composite-map - A module for mapping between multi-part keys and values.
• json-key-map - A module for mapping between JSON keys and values.

License

MIT

Sources

Some text from this readme was sourced from developer.mozilla.org.