angular2/es6/prod/src/common/pipes/slice_pipe.js

Angular 2 - a web framework for modern web apps

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};
import { isBlank, isString, isArray, StringWrapper } from 'angular2/src/facade/lang';
import { BaseException } from 'angular2/src/facade/exceptions';
import { ListWrapper } from 'angular2/src/facade/collection';
import { Injectable, Pipe } from 'angular2/core';
import { InvalidPipeArgumentException } from './invalid_pipe_argument_exception';
/**
 * Creates a new List or String containing only a subset (slice) of the
 * elements.
 *
 * The starting index of the subset to return is specified by the `start` parameter.
 *
 * The ending index of the subset to return is specified by the optional `end` parameter.
 *
 * ### Usage
 *
 *     expression | slice:start[:end]
 *
 * All behavior is based on the expected behavior of the JavaScript API
 * Array.prototype.slice() and String.prototype.slice()
 *
 * Where the input expression is a [List] or [String], and `start` is:
 *
 * - **a positive integer**: return the item at _start_ index and all items after
 * in the list or string expression.
 * - **a negative integer**: return the item at _start_ index from the end and all items after
 * in the list or string expression.
 * - **`|start|` greater than the size of the expression**: return an empty list or string.
 * - **`|start|` negative greater than the size of the expression**: return entire list or
 * string expression.
 *
 * and where `end` is:
 *
 * - **omitted**: return all items until the end of the input
 * - **a positive integer**: return all items before _end_ index of the list or string
 * expression.
 * - **a negative integer**: return all items before _end_ index from the end of the list
 * or string expression.
 *
 * When operating on a [List], the returned list is always a copy even when all
 * the elements are being returned.
 *
 * ## List Example
 *
 * This `ng-for` example:
 *
 * {@example core/pipes/ts/slice_pipe/slice_pipe_example.ts region='SlicePipe_list'}
 *
 * produces the following:
 *
 *     <li>b</li>
 *     <li>c</li>
 *
 * ## String Examples
 *
 * {@example core/pipes/ts/slice_pipe/slice_pipe_example.ts region='SlicePipe_string'}
 */
export let SlicePipe = class {
    transform(value, args = null) {
        if (isBlank(args) || args.length == 0) {
            throw new BaseException('Slice pipe requires one argument');
        }
        if (!this.supports(value)) {
            throw new InvalidPipeArgumentException(SlicePipe, value);
        }
        if (isBlank(value))
            return value;
        var start = args[0];
        var end = args.length > 1 ? args[1] : null;
        if (isString(value)) {
            return StringWrapper.slice(value, start, end);
        }
        return ListWrapper.slice(value, start, end);
    }
    supports(obj) { return isString(obj) || isArray(obj); }
};
SlicePipe = __decorate([
    Pipe({ name: 'slice', pure: false }),
    Injectable(), 
    __metadata('design:paramtypes', [])
], SlicePipe);