immutable-js/src/List.js

Immutable types in JavaScript

/**
 *  Copyright (c) 2015, Jan Biasi.
 *  All rights reserved.
 *
 *  This source code is licensed under the BSD-style license found in the
 *  LICENSE file in the root directory of this source tree. An additional grant
 *  of patent rights can be found in the PATENTS file in the same directory.
 */

import { IndexedCollection } from './Collection';
import { IS_LIST_FLAG, isList } from './Flags';
import { NativeArray, NativeObject, isNative } from './Native';
import { nullOrUndefined } from './util/is';
import { typedef as defineTypeOf } from './util/toolset';

export var LIST_TYPEDEF = '[IndexedCollection List]';
export class List extends IndexedCollection {
    constructor(value) {
        return arguments.length > 1 ? makeList(
            Array.prototype.slice.call(arguments)
        ) : makeList(value);
    }

    static of (...values) {
        return this(values);
    }

    toString() {
        return this.__toString('List [', this.__internal.join(',') ,']');
    }

    push(...values) {
        if(this.__ownerID) {
            values.forEach(v => this.__internal.push(v));
            this.size = this.__internal.length;
            this.__altered = true;
            return this;
        }
        return makeList(this.__internal.__clone().concat(values));
    }

    shift() {
        if(this.__ownerID) {
            this.__internal.pop();
            this.size = this.__internal.length;
            this.__altered = true;
            return this;
        }
        var cloned = this.__internal.__clone();
        var newSize = cloned.pop();
        return new List(cloned);
    }

    clean() {
        if(this.size === 0) {
            return this;
        }
        if(this.__ownerID) {
            this.__altered = true;
            this.__internal = new NativeArray();
            this.size = this.__internal.length;
            return this;
        }
        return emptyList();
    }

    __iterator(handle, reverse) {

    }

    __ensureOwner(ownerID) {
        if(ownerID === this.__ownerID) {
            return this;
        }
        if(!ownerID || nullOrUndefined(ownerID)) {
            this.__ownerID = ownerID;
            this.__altered = false;
            return this;
        }
        return makeList(this.__internal, ownerID);
    }
}

var EMPTY_LIST;
function emptyList() {
    return EMPTY_LIST || (EMPTY_LIST = makeList(null));
}

function makeList(values, ownerID) {
    var list = Object.create(List.prototype);
    list.__ownerID = ownerID;
    list.__altered = false;
    list.__internal = new NativeArray();
    list.size = 0;
    if(nullOrUndefined(values)) {
        return list;
    } else if(isNative(values)) {
        list.__internal = values;
    } else if (Array.isArray(values)) {
        list.__internal = new NativeArray();
        values.forEach((value, index) => {
            list.__internal.push(value);
        });
        list.size = list.__internal.length;
    } else {
        throw TypeError(
            'Expected an array or values as input and not ' +
            typeof values
        );
    }
    return list;
}

defineTypeOf({
    List: LIST_TYPEDEF
});

List.prototype[IS_LIST_FLAG] = true;
List.isList = isList;