refactor(pipes): remove LimitTo pipe in favor of slice pipe

modules/angular2/src/core/facade/collection.dart

@@ -182,11 +182,13 @@ class ListWrapper {
   }
 
   static List slice(List l, [int from = 0, int to]) {
+    from = _startOffset(l, from);
+    to = _endOffset(l, to);
     //in JS if from > to an empty array is returned
     if(to != null && from > to) {
       return [];
     }
-    return l.sublist(_startOffset(l, from), _endOffset(l, to));
+    return l.sublist(from, to);
   }
 
   static List splice(List l, int from, int length) {
@@ -213,7 +215,7 @@ class ListWrapper {
   // the end of the list
   static int _startOffset(List l, int start) {
     int len = l.length;
-    return start = start < 0 ? max(len + start, 0) : min(start, len);
+    return start < 0 ? max(len + start, 0) : min(start, len);
   }
 
   // JS splice, slice, fill functions can take end < 0 which indicates a position relative to

modules/angular2/src/core/facade/lang.dart

@@ -95,11 +95,13 @@ class StringWrapper {
   }
 
   static String slice(String s, [int start = 0, int end]) {
+    start = _startOffset(s, start);
+    end = _endOffset(s, end);
     //in JS if start > end an empty string is returned
     if(end != null && start > end) {
       return "";
     }
-    return s.substring(_startOffset(s, start), _endOffset(s, end));
+    return s.substring(start, end);
   }
 
   static String substring(String s, int start, [int end]) {
@@ -120,7 +122,7 @@ class StringWrapper {
   // the end of the string
   static int _startOffset(String s, int start) {
     int len = s.length;
-    return start = start < 0 ? math.max(len + start, 0) : math.min(start, len);
+    return start < 0 ? math.max(len + start, 0) : math.min(start, len);
   }
 
   // JS slice function can take end < 0 which indicates a position relative to

modules/angular2/src/core/pipes.ts

@@ -8,7 +8,7 @@ export {AsyncPipe} from './pipes/async_pipe';
 export {DatePipe} from './pipes/date_pipe';
 export {DEFAULT_PIPES, DEFAULT_PIPES_TOKEN} from './pipes/default_pipes';
 export {JsonPipe} from './pipes/json_pipe';
-export {LimitToPipe} from './pipes/limit_to_pipe';
+export {SlicePipe} from './pipes/slice_pipe';
 export {LowerCasePipe} from './pipes/lowercase_pipe';
 export {NumberPipe, DecimalPipe, PercentPipe, CurrencyPipe} from './pipes/number_pipe';
 export {UpperCasePipe} from './pipes/uppercase_pipe';

modules/angular2/src/core/pipes/default_pipes.ts

@@ -2,7 +2,7 @@ import {AsyncPipe} from './async_pipe';
 import {UpperCasePipe} from './uppercase_pipe';
 import {LowerCasePipe} from './lowercase_pipe';
 import {JsonPipe} from './json_pipe';
-import {LimitToPipe} from './limit_to_pipe';
+import {SlicePipe} from './slice_pipe';
 import {DatePipe} from './date_pipe';
 import {DecimalPipe, PercentPipe, CurrencyPipe} from './number_pipe';
 
@@ -14,7 +14,7 @@ const DEFAULT_PIPES_LIST = CONST_EXPR([
   UpperCasePipe,
   LowerCasePipe,
   JsonPipe,
-  LimitToPipe,
+  SlicePipe,
   DecimalPipe,
   PercentPipe,
   CurrencyPipe,

modules/angular2/src/core/pipes/limit_to_pipe.ts

@@ -1,73 +0,0 @@
-import {isBlank, isString, isArray, StringWrapper, CONST} from 'angular2/src/core/facade/lang';
-import {BaseException, WrappedException} from 'angular2/src/core/facade/exceptions';
-import {ListWrapper} from 'angular2/src/core/facade/collection';
-import {Math} from 'angular2/src/core/facade/math';
-import {PipeTransform, WrappedValue} from 'angular2/src/core/change_detection';
-import {Injectable} from 'angular2/src/core/di';
-import {Pipe} from 'angular2/src/core/metadata';
-import {InvalidPipeArgumentException} from './invalid_pipe_argument_exception';
-
-/**
- * Creates a new Array or String containing only a prefix/suffix of the
- * elements.
- *
- * The number of elements to return is specified by the `limitTo` parameter.
- *
- * # Usage
- *
- *     expression | limitTo:number
- *
- * Where the input expression is a [Array] or [String], and `limitTo` is:
- *
- * - **a positive integer**: return _number_ items from the beginning of the list or string
- * expression.
- * - **a negative integer**: return _number_ items from the end of the list or string expression.
- * - **`|limitTo|` greater than the size of the expression**: return the entire expression.
- *
- * When operating on a [Array], the returned list is always a copy even when all
- * the elements are being returned.
- *
- * # Examples
- *
- * ## Array Example
- *
- * Assuming `var collection = ['a', 'b', 'c']`, this `ng-for` directive:
- *
- *     <li *ng-for="var i in collection | limitTo:2">{{i}}</li>
- *
- * produces the following:
- *
- *     <li>a</li>
- *     <li>b</li>
- *
- * ## String Examples
- *
- *     {{ 'abcdefghij' | limitTo: 4 }}       // output is 'abcd'
- *     {{ 'abcdefghij' | limitTo: -4 }}      // output is 'ghij'
- *     {{ 'abcdefghij' | limitTo: -100 }}    // output is 'abcdefghij'
- */
-@Pipe({name: 'limitTo'})
-@Injectable()
-export class LimitToPipe implements PipeTransform {
-  supports(obj: any): boolean { return isString(obj) || isArray(obj); }
-
-  transform(value: any, args: any[] = null): any {
-    if (isBlank(args) || args.length == 0) {
-      throw new BaseException('limitTo pipe requires one argument');
-    }
-    if (!this.supports(value)) {
-      throw new InvalidPipeArgumentException(LimitToPipe, value);
-    }
-    if (isBlank(value)) return value;
-    var limit: number = args[0];
-    var left = 0, right = Math.min(limit, value.length);
-    if (limit < 0) {
-      left = Math.max(0, value.length + limit);
-      right = value.length;
-    }
-    if (isString(value)) {
-      return StringWrapper.substring(value, left, right);
-    }
-    return ListWrapper.slice(value, left, right);
-  }
-}

modules/angular2/src/core/pipes/slice_pipe.ts

@@ -3,9 +3,9 @@ import {
   isString,
   isArray,
   StringWrapper,
-  BaseException,
   CONST
 } from 'angular2/src/core/facade/lang';
+import {BaseException} from 'angular2/src/core/facade/exceptions';
 import {ListWrapper} from 'angular2/src/core/facade/collection';
 import {Injectable} from 'angular2/di';
 
@@ -76,7 +76,7 @@ import {Pipe} from '../metadata';
 @Pipe({name: 'slice'})
 @Injectable()
 export class SlicePipe implements PipeTransform {
-  transform(value: any, args: List<any> = null): any {
+  transform(value: any, args: any[] = null): any {
     if (isBlank(args) || args.length == 0) {
       throw new BaseException('Slice pipe requires one argument');
     }
@@ -85,7 +85,7 @@ export class SlicePipe implements PipeTransform {
     }
     if (isBlank(value)) return value;
     var start: number = args[0];
-    var end: number = args.length > 1 ? args[1] : value.length;
+    var end: number = args.length > 1 ? args[1] : null;
     if (isString(value)) {
       return StringWrapper.slice(value, start, end);
     }

modules/angular2/test/core/facade/collection_spec.ts

@@ -63,8 +63,10 @@ export function main() {
       it('should support negative end',
          () => { expect(ListWrapper.slice(l, -3, -1)).toEqual([2, 3]); });
 
-      it('should return empty list if start is greater than end',
-         () => { expect(ListWrapper.slice(l, 4, 2)).toEqual([]); });
+      it('should return empty list if start is greater than end', () => {
+        expect(ListWrapper.slice(l, 4, 2)).toEqual([]);
+        expect(ListWrapper.slice(l, -2, -4)).toEqual([]);
+      });
     });
 
     describe('indexOf', () => {

modules/angular2/test/core/facade/lang_spec.ts

@@ -76,8 +76,10 @@ export function main() {
       it('should support negative end',
          () => { expect(StringWrapper.slice(s, -3, -1)).toEqual("hi"); });
 
-      it('should return empty string if start is greater than end',
-         () => { expect(StringWrapper.slice(s, 4, 2)).toEqual(""); });
+      it('should return empty string if start is greater than end', () => {
+        expect(StringWrapper.slice(s, 4, 2)).toEqual("");
+        expect(StringWrapper.slice(s, -2, -4)).toEqual("");
+      });
     });
 
   });

modules/angular2/test/core/pipes/limit_to_pipe_spec.ts

@@ -1,57 +0,0 @@
-import {ddescribe, describe, it, iit, xit, expect, beforeEach, afterEach} from 'angular2/test_lib';
-
-import {LimitToPipe} from 'angular2/core';
-
-export function main() {
-  describe("LimitToPipe", () => {
-    var list;
-    var str;
-    var pipe;
-
-    beforeEach(() => {
-      list = [1, 2, 3, 4, 5];
-      str = 'tuvwxyz';
-      pipe = new LimitToPipe();
-    });
-
-    describe("supports", () => {
-      it("should support strings", () => { expect(pipe.supports(str)).toBe(true); });
-      it("should support lists", () => { expect(pipe.supports(list)).toBe(true); });
-
-      it("should not support other objects", () => {
-        expect(pipe.supports(new Object())).toBe(false);
-        expect(pipe.supports(null)).toBe(false);
-      });
-    });
-
-    describe("transform", () => {
-
-      it('should return the first X items when X is positive', () => {
-        expect(pipe.transform(list, [3])).toEqual([1, 2, 3]);
-        expect(pipe.transform(str, [3])).toEqual('tuv');
-      });
-
-      it('should return the last X items when X is negative', () => {
-        expect(pipe.transform(list, [-3])).toEqual([3, 4, 5]);
-        expect(pipe.transform(str, [-3])).toEqual('xyz');
-      });
-
-      it('should return a copy of input array if X is exceeds array length', () => {
-        expect(pipe.transform(list, [20])).toEqual(list);
-        expect(pipe.transform(list, [-20])).toEqual(list);
-      });
-
-      it('should return the entire string if X exceeds input length', () => {
-        expect(pipe.transform(str, [20])).toEqual(str);
-        expect(pipe.transform(str, [-20])).toEqual(str);
-      });
-
-      it('should not modify the input list', () => {
-        expect(pipe.transform(list, [3])).toEqual([1, 2, 3]);
-        expect(list).toEqual([1, 2, 3, 4, 5]);
-      });
-
-    });
-
-  });
-}