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// Copyright (C) 2017 Valerie Young. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
esid: sec-string.prototype.trimStart
description: >
This value is an object which cannot be converted to a primitive
info: |
Runtime Semantics: TrimString ( string, where )
1. Let str be ? RequireObjectCoercible(string).
2. Let S be ? ToString(str).
...
ToString ( argument )
If argument is Object:
1. Let primValue be ? ToPrimitive(argument, hint String).
...
ToPrimitive ( input [, PreferredType ])
...
b. Else if PreferredType is hint String, let hint be "string".
...
d. Let exoticToPrim be ? GetMethod(input, @@toPrimitive)
e. If exoticToPrim is not undefined, then
i. Let result be ? Call(exoticToPrim, input, « hint »).
ii. If Type(result) is not Object, return result.
iii. Throw a TypeError exception.
f. If hint is "default", set hint to "number".
g. Return ? OrdinaryToPrimitive(input, hint).
...
OrdinaryToPrimitive( O, hint )
...
3. If hint is "string", then
a. Let methodNames be « "toString", "valueOf" ».
...
5. For each name in methodNames in List order, do
a. Let method be ? Get(O, name).
b. If IsCallable(method) is true, then
i. Let result be ? Call(method, O).
ii. If Type(result) is not Object, return result.
6. Throw a TypeError exception.
features: [string-trimming, String.prototype.trimStart, Symbol.toPrimitive]
---*/
var thisVal = {
[Symbol.toPrimitive]: undefined,
toString: undefined,
valueOf: undefined,
};
// If trimStart is called on an object with neither Symbol.toPrimitive, toString
// nor valueOf defined, then a TypeError exception should be thrown.
assert.throws(
TypeError,
function() {
String.prototype.trimStart.call(thisVal);
},
);
|