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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: >
Priority of Symbol[toPrimitive] when converting object to string for trimming
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 ])
...
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.
...
features: [string-trimming, String.prototype.trimStart, Symbol.toPrimitive]
---*/
var toPrimitiveAccessed = 0;
var toStringAccessed = 0;
var valueOfAccessed = 0;
var thisVal = {
get [Symbol.toPrimitive]() {
toPrimitiveAccessed += 1;
return function() {
return ' 42';
};
},
get toString() {
toStringAccessed += 1;
return function() {
return '';
};
},
get valueOf() {
valueOfAccessed += 1;
return function() {
return '';
};
},
};
// Test that thisVal[Symbol.toPrimitive] has been called.
var result = String.prototype.trimStart.call(thisVal);
assert.sameValue(
toPrimitiveAccessed,
1,
'thisVal[Symbol.toPrimitive] expected to have been accessed.'
);
assert.sameValue(
result,
'42',
'thisVal[Symbol.toPrimitive] expected to have been called.',
);
// Test that thisVal.toString and thisVal.valueOf have not been accessedo
assert.sameValue(
toStringAccessed,
0,
'thisVal.toString should not have been accessed.'
);
assert.sameValue(
valueOfAccessed,
0,
'thisVal.valueOf should not have been accessed.'
);
|
