String.prototype.startsWith

test/built-ins/String/prototype/startsWith/coerced-values-of-position.js

@@ -0,0 +1,39 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 21.1.3.18
+description: >
+  Returns based on coerced values of position.
+info: >
+  21.1.3.18 String.prototype.startsWith ( searchString [ , position ] )
+
+  ...
+  9. Let pos be ToInteger(position). (If position is undefined, this step
+  produces the value 0).
+  10. ReturnIfAbrupt(pos).
+  11. Let len be the number of elements in S.
+  12. Let start be min(max(pos, 0), len).
+  13. Let searchLength be the number of elements in searchStr.
+  14. If searchLength+start is greater than len, return false.
+  15. If the sequence of elements of S starting at start of length searchLength
+  is the same as the full element sequence of searchStr, return true.
+  16. Otherwise, return false.
+  ...
+---*/
+
+var str = 'The future is cool!';
+
+assert(str.startsWith('The future', NaN), 'NaN coerced to 0');
+assert(str.startsWith('The future', null), 'null coerced to 0');
+assert(str.startsWith('The future', false), 'false coerced to 0');
+assert(str.startsWith('The future', ''), '"" coerced to 0');
+assert(str.startsWith('The future', '0'), '"0" coerced to 0');
+assert(str.startsWith('The future', undefined), 'undefined coerced to 0');
+assert(str.startsWith('The future', 0.4), '0.4 coerced to 0');
+
+assert.sameValue(
+  str.startsWith('The future', true), false,
+  'true coerced to 1'
+);
+assert.sameValue(str.startsWith('The future', '1'), false, '"1" coerced to 1');
+assert.sameValue(str.startsWith('The future', 1.4), false, '1.4 coerced to 1');

test/built-ins/String/prototype/startsWith/length.js

@@ -0,0 +1,22 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 21.1.3.18
+description: >
+  String.prototype.startsWith.length value and descriptor.
+info: >
+  21.1.3.18 String.prototype.startsWith ( searchString [ , position ] )
+
+  The length property of the startsWith method is 1.
+
+includes: [propertyHelper.js]
+---*/
+
+assert.sameValue(
+  String.prototype.startsWith.length, 1,
+  'The value of `String.prototype.startsWith.length` is `1`'
+);
+
+verifyNotEnumerable(String.prototype.startsWith, 'length');
+verifyNotWritable(String.prototype.startsWith, 'length');
+verifyConfigurable(String.prototype.startsWith, 'length');

test/built-ins/String/prototype/startsWith/name.js

@@ -0,0 +1,22 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 21.1.3.18
+description: >
+  String.prototype.startsWith.name value and descriptor.
+info: >
+  21.1.3.18 String.prototype.startsWith ( searchString [ , position ] )
+
+  17 ECMAScript Standard Built-in Objects
+
+includes: [propertyHelper.js]
+---*/
+
+assert.sameValue(
+  String.prototype.startsWith.name, 'startsWith',
+  'The value of `String.prototype.startsWith.name` is `"startsWith"`'
+);
+
+verifyNotEnumerable(String.prototype.startsWith, 'name');
+verifyNotWritable(String.prototype.startsWith, 'name');
+verifyConfigurable(String.prototype.startsWith, 'name');

test/built-ins/String/prototype/startsWith/out-of-bounds-position.js

@@ -0,0 +1,43 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 21.1.3.18
+description: >
+  Returns false if searchLength + start position is greater than string length.
+info: >
+  21.1.3.18 String.prototype.startsWith ( searchString [ , position ] )
+
+  ...
+  11. Let len be the number of elements in S.
+  12. Let start be min(max(pos, 0), len).
+  13. Let searchLength be the number of elements in searchStr.
+  14. If searchLength+start is greater than len, return false.
+  ...
+---*/
+
+var str = 'The future is cool!';
+
+assert.sameValue(
+  str.startsWith('!', str.length), false,
+  'str.startsWith("!", str.length) returns false'
+);
+
+assert.sameValue(
+  str.startsWith('!', 100), false,
+  'str.startsWith("!", 100) returns false'
+);
+
+assert.sameValue(
+  str.startsWith('!', Infinity), false,
+  'str.startsWith("!", Infinity) returns false'
+);
+
+assert(
+  str.startsWith('The future', -1),
+  'position argument < 0 will search from the start of the string (-1)'
+);
+
+assert(
+  str.startsWith('The future', -Infinity),
+  'position argument < 0 will search from the start of the string (-Infinity)'
+);

test/built-ins/String/prototype/startsWith/return-abrupt-from-position-as-symbol.js

@@ -0,0 +1,22 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 21.1.3.18
+description: >
+  Returns abrupt from ToInteger(position) as a Symbol.
+info: >
+  21.1.3.18 String.prototype.startsWith ( searchString [ , position ] )
+
+  ...
+  9. Let pos be ToInteger(position). (If position is undefined, this step
+  produces the value 0).
+  10. ReturnIfAbrupt(pos).
+  ...
+features: [Symbol]
+---*/
+
+var position = Symbol();
+
+assert.throws(TypeError, function() {
+  ''.startsWith('', position);
+});

test/built-ins/String/prototype/startsWith/return-abrupt-from-position.js

@@ -0,0 +1,25 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 21.1.3.18
+description: >
+  Returns abrupt from ToInteger(position).
+info: >
+  21.1.3.18 String.prototype.startsWith ( searchString [ , position ] )
+
+  ...
+  9. Let pos be ToInteger(position). (If position is undefined, this step
+  produces the value 0).
+  10. ReturnIfAbrupt(pos).
+  ...
+---*/
+
+var position = {
+  valueOf: function() {
+    throw new Test262Error();
+  }
+};
+
+assert.throws(Test262Error, function() {
+  ''.startsWith('', position);
+});

test/built-ins/String/prototype/startsWith/return-abrupt-from-searchstring-as-symbol.js

@@ -0,0 +1,21 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 21.1.3.18
+description: >
+  Returns abrupt from ToString(searchString) as a Symbol
+info: >
+  21.1.3.18 String.prototype.startsWith ( searchString [ , position ] )
+
+  ...
+  7. Let searchStr be ToString(searchString).
+  8. ReturnIfAbrupt(searchString).
+  ...
+features: [Symbol]
+---*/
+
+var s = Symbol();
+
+assert.throws(TypeError, function() {
+  ''.startsWith(s);
+});

test/built-ins/String/prototype/startsWith/return-abrupt-from-searchstring-regexp-test.js

@@ -0,0 +1,42 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 21.1.3.18
+description: >
+  Returns abrupt from IsRegExp(searchString).
+info: >
+  21.1.3.18 String.prototype.startsWith ( searchString [ , position ] )
+
+  ...
+  4. Let isRegExp be IsRegExp(searchString).
+  5. ReturnIfAbrupt(isRegExp).
+  ...
+
+  7.2.8 IsRegExp ( argument )
+
+  2. Let isRegExp be Get(argument, @@match).
+  3. ReturnIfAbrupt(isRegExp).
+features: [Symbol.match]
+---*/
+
+var obj = {};
+Object.defineProperty(obj, Symbol.match, {
+  get: function() {
+    throw new Test262Error();
+  }
+});
+
+assert.throws(Test262Error, function() {
+  ''.startsWith(obj);
+});
+
+var regexp = /./;
+Object.defineProperty(regexp, Symbol.match, {
+  get: function() {
+    throw new Test262Error();
+  }
+});
+
+assert.throws(Test262Error, function() {
+  ''.startsWith(regexp);
+});

test/built-ins/String/prototype/startsWith/return-abrupt-from-searchstring.js

@@ -0,0 +1,24 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 21.1.3.18
+description: >
+  Returns abrupt from ToString(searchString)
+info: >
+  21.1.3.18 String.prototype.startsWith ( searchString [ , position ] )
+
+  ...
+  7. Let searchStr be ToString(searchString).
+  8. ReturnIfAbrupt(searchString).
+  ...
+---*/
+
+var obj = {
+  toString: function() {
+    throw new Test262Error();
+  }
+};
+
+assert.throws(Test262Error, function() {
+  ''.startsWith(obj);
+});

test/built-ins/String/prototype/startsWith/return-abrupt-from-this-as-symbol.js

@@ -0,0 +1,20 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 21.1.3.18
+description: >
+  Returns abrupt from ToString(this) where this is a Symbol
+info: >
+  21.1.3.18 String.prototype.startsWith ( searchString [ , position ] )
+
+  1. Let O be RequireObjectCoercible(this value).
+  2. Let S be ToString(O).
+  3. ReturnIfAbrupt(S).
+features: [Symbol]
+---*/
+
+var s = Symbol('');
+
+assert.throws(TypeError, function() {
+  String.prototype.startsWith.call(s, '');
+});

test/built-ins/String/prototype/startsWith/return-abrupt-from-this.js

@@ -0,0 +1,23 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 21.1.3.18
+description: >
+  Returns abrupt from ToString(this)
+info: >
+  21.1.3.18 String.prototype.startsWith ( searchString [ , position ] )
+
+  1. Let O be RequireObjectCoercible(this value).
+  2. Let S be ToString(O).
+  3. ReturnIfAbrupt(S).
+---*/
+
+var o = {
+  toString: function() {
+    throw new Test262Error();
+  }
+};
+
+assert.throws(Test262Error, function() {
+  String.prototype.startsWith.call(o, '');
+});

test/built-ins/String/prototype/startsWith/return-true-if-searchstring-is-empty.js

@@ -0,0 +1,40 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 21.1.3.18
+description: >
+  Returns true if searchString.length == 0.
+info: >
+  21.1.3.18 String.prototype.startsWith ( searchString [ , position ] )
+
+  ...
+  11. Let len be the number of elements in S.
+  12. Let start be min(max(pos, 0), len).
+  13. Let searchLength be the number of elements in searchStr.
+  14. If searchLength+start is greater than len, return false.
+  15. If the sequence of elements of S starting at start of length searchLength
+  is the same as the full element sequence of searchStr, return true.
+  ...
+---*/
+
+var str = 'The future is cool!';
+
+assert(
+  str.startsWith(''),
+  'str.startsWith("") returns true'
+);
+
+assert(
+  str.startsWith('', str.length),
+  'str.startsWith("", str.length) returns true'
+);
+
+assert(
+  str.startsWith(''),
+  'str.startsWith("") returns true'
+);
+
+assert(
+  str.startsWith('', Infinity),
+  'str.startsWith("", Infinity) returns true'
+);

test/built-ins/String/prototype/startsWith/searchstring-found-with-position.js

@@ -0,0 +1,34 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 21.1.3.18
+description: >
+  Returns true if searchString appears as a substring of the given string with a
+  given position.
+info: >
+  21.1.3.18 String.prototype.startsWith ( searchString [ , position ] )
+
+  ...
+  11. Let len be the number of elements in S.
+  12. Let start be min(max(pos, 0), len).
+  13. Let searchLength be the number of elements in searchStr.
+  14. If searchLength+start is greater than len, return false.
+  15. If the sequence of elements of S starting at start of length searchLength
+  is the same as the full element sequence of searchStr, return true.
+  ...
+---*/
+
+var str = 'The future is cool!';
+
+assert(
+  str.startsWith('The future', 0),
+  'str.startsWith("The future", 0) === true'
+);
+assert(
+  str.startsWith('future', 4),
+  'str.startsWith("future", 4) === true'
+);
+assert(
+  str.startsWith(' is cool!', 10),
+  'str.startsWith(" is cool!", 10) === true'
+);

test/built-ins/String/prototype/startsWith/searchstring-found-without-position.js

@@ -0,0 +1,24 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 21.1.3.18
+description: >
+  Returns true if searchString appears as a substring of the given string.
+info: >
+  21.1.3.18 String.prototype.startsWith ( searchString [ , position ] )
+
+  ...
+  11. Let len be the number of elements in S.
+  12. Let start be min(max(pos, 0), len).
+  13. Let searchLength be the number of elements in searchStr.
+  14. If searchLength+start is greater than len, return false.
+  15. If the sequence of elements of S starting at start of length searchLength
+  is the same as the full element sequence of searchStr, return true.
+  ...
+---*/
+
+var str = 'The future is cool!';
+
+assert(str.startsWith('The '), 'str.startsWith("The ") === true');
+assert(str.startsWith('The future'), 'str.startsWith("The future") === true');
+assert(str.startsWith(str), 'str.startsWith(str) === true');

test/built-ins/String/prototype/startsWith/searchstring-is-regexp-throws.js

@@ -0,0 +1,21 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 21.1.3.18
+description: >
+  Throws a TypeError if searchString is a RegExp.
+info: >
+  21.1.3.18 String.prototype.startsWith ( searchString [ , position ] )
+
+  ...
+  4. Let isRegExp be IsRegExp(searchString).
+  5. ReturnIfAbrupt(isRegExp).
+  6. If isRegExp is true, throw a TypeError exception.
+  ...
+---*/
+
+var searchString = /./;
+
+assert.throws(TypeError, function() {
+  ''.startsWith(searchString);
+});

test/built-ins/String/prototype/startsWith/searchstring-not-found-with-position.js

@@ -0,0 +1,31 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 21.1.3.18
+description: >
+  Returns false if searchString is not found with a given position.
+info: >
+  21.1.3.18 String.prototype.startsWith ( searchString [ , position ] )
+
+  ...
+  11. Let len be the number of elements in S.
+  12. Let start be min(max(pos, 0), len).
+  13. Let searchLength be the number of elements in searchStr.
+  14. If searchLength+start is greater than len, return false.
+  15. If the sequence of elements of S starting at start of length searchLength
+  is the same as the full element sequence of searchStr, return true.
+  16. Otherwise, return false.
+  ...
+---*/
+
+var str = 'The future is cool!';
+
+assert.sameValue(
+  str.startsWith('The future', 1), false,
+  'str.startsWith("The future", 1) === false'
+);
+
+assert.sameValue(
+  str.startsWith(str, 1), false,
+  'str.startsWith(str, 1) === false'
+);

test/built-ins/String/prototype/startsWith/searchstring-not-found-without-position.js

@@ -0,0 +1,34 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 21.1.3.18
+description: >
+  Returns false if searchString is not found.
+info: >
+  21.1.3.18 String.prototype.startsWith ( searchString [ , position ] )
+
+  ...
+  11. Let len be the number of elements in S.
+  12. Let start be min(max(pos, 0), len).
+  13. Let searchLength be the number of elements in searchStr.
+  14. If searchLength+start is greater than len, return false.
+  15. If the sequence of elements of S starting at start of length searchLength
+  is the same as the full element sequence of searchStr, return true.
+  16. Otherwise, return false.
+  ...
+---*/
+
+var str = 'The future is cool!';
+
+assert.sameValue(
+  str.startsWith('Flash'), false,
+  'str.startsWith("Flash") === false'
+);
+assert.sameValue(
+  str.startsWith('THE FUTURE'), false,
+  'startsWith is case sensitive'
+);
+assert.sameValue(
+  str.startsWith('future is cool!'), false,
+  'str.startsWith("future is cool!") === false'
+);

test/built-ins/String/prototype/startsWith/startsWith.js

@@ -0,0 +1,22 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 21.1.3.18
+description: >
+  Property type and descriptor.
+info: >
+  21.1.3.18 String.prototype.startsWith ( searchString [ , position ] )
+
+  17 ECMAScript Standard Built-in Objects
+includes: [propertyHelper.js]
+---*/
+
+assert.sameValue(
+  typeof String.prototype.startsWith,
+  'function',
+  '`typeof String.prototype.startsWith` is `function`'
+);
+
+verifyNotEnumerable(String.prototype, 'startsWith');
+verifyWritable(String.prototype, 'startsWith');
+verifyConfigurable(String.prototype, 'startsWith');

test/built-ins/String/prototype/startsWith/this-is-null-throws.js

@@ -0,0 +1,16 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 21.1.3.18
+description: >
+  Throws TypeError when `this` is null
+info: >
+  21.1.3.18 String.prototype.startsWith ( searchString [ , position ] )
+
+  1. Let O be RequireObjectCoercible(this value).
+  2. Let S be ToString(O).
+---*/
+
+assert.throws(TypeError, function() {
+  String.prototype.startsWith.call(null, '');
+});

test/built-ins/String/prototype/startsWith/this-is-undefined-throws.js

@@ -0,0 +1,16 @@
+// Copyright (C) 2015 the V8 project authors. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+es6id: 21.1.3.18
+description: >
+  Throws TypeError when `this` is undefined
+info: >
+  21.1.3.18 String.prototype.startsWith ( searchString [ , position ] )
+
+  1. Let O be RequireObjectCoercible(this value).
+  2. Let S be ToString(O).
+---*/
+
+assert.throws(TypeError, function() {
+  String.prototype.startsWith.call(undefined, '');
+});