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ec88c68c28
Compress `a || (a = b)` to `a ||= b` and for other logical operators that are possible to. I didn't find other minifiers doing this, but this is safe for identifiers. [Quoting MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Logical_OR_assignment#description): > Logical OR assignment short-circuits, meaning that `x ||= y` is equivalent to `x || (x = y)`, except that the expression x is only evaluated once. I actually checked the spec and the only difference was that `Let lRef be ? Evaluation of LeftHandSideExpression` was done twice. Evaluating an IdentifierReference is idempotent so it should be safe to do this compression. References: - [Spec of `&&=`](https://tc39.es/ecma262/multipage/ecmascript-language-expressions.html#sec-assignment-operators:~:text=Return%20r.-,AssignmentExpression,7.%20Return%20rVal.,-AssignmentExpression) - [Spec of `=`](https://tc39.es/ecma262/multipage/ecmascript-language-expressions.html#prod-AssignmentExpression:~:text=Runtime%20Semantics%3A%20Evaluation-,AssignmentExpression,6.%20Return%20rVal.,-AssignmentExpression) - [Spec of `&&`](https://tc39.es/ecma262/multipage/ecmascript-language-expressions.html#sec-binary-logical-operators:~:text=Runtime%20Semantics%3A%20Evaluation-,LogicalANDExpression,5.%20Return%20%3F%C2%A0GetValue(rRef).,-LogicalORExpression) I think this is safe for `a.b || (a.b = foo)` as well because the number of `GetValue` and `SetValue` does not change, but I didn't include that in this PR. |
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| ast_tools | ||
| benchmark | ||
| common | ||
| compat_data | ||
| coverage | ||
| javascript_globals | ||
| lint_rules | ||
| minsize | ||
| prettier_conformance | ||
| rulegen | ||
| transform_checker | ||
| transform_conformance | ||
| website | ||