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fix commit 88fb83a (#1622)

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The following is wrong:
    `a == (b ? a : c)` => `b`
Because:
- `b` may not be boolean
- `a` might have side effects
- `a == a` is not always `true` (think `NaN`)
- `a == c` is not always `false`
This commit is contained in:
Alex Lam S.L
2017-03-19 11:59:42 +08:00
committed by GitHub
parent cd58635dcc
commit 96f8befdd7
2 changed files with 96 additions and 26 deletions
Download Patch File Download Diff File Expand all files Collapse all files

26
lib/compress.js
View File

@@ -3057,32 +3057,6 @@ merge(Compressor.prototype, {
reverse();
}
}
if (/^[!=]==?$/.test(self.operator)) {
if (self.left instanceof AST_SymbolRef && self.right instanceof AST_Conditional) {
if (self.right.consequent instanceof AST_SymbolRef
&& self.right.consequent.definition() === self.left.definition()) {
if (/^==/.test(self.operator)) return self.right.condition;
if (/^!=/.test(self.operator)) return self.right.condition.negate(compressor);
}
if (self.right.alternative instanceof AST_SymbolRef
&& self.right.alternative.definition() === self.left.definition()) {
if (/^==/.test(self.operator)) return self.right.condition.negate(compressor);
if (/^!=/.test(self.operator)) return self.right.condition;
}
}
if (self.right instanceof AST_SymbolRef && self.left instanceof AST_Conditional) {
if (self.left.consequent instanceof AST_SymbolRef
&& self.left.consequent.definition() === self.right.definition()) {
if (/^==/.test(self.operator)) return self.left.condition;
if (/^!=/.test(self.operator)) return self.left.condition.negate(compressor);
}
if (self.left.alternative instanceof AST_SymbolRef
&& self.left.alternative.definition() === self.right.definition()) {
if (/^==/.test(self.operator)) return self.left.condition.negate(compressor);
if (/^!=/.test(self.operator)) return self.left.condition;
}
}
}
}
self = self.lift_sequences(compressor);
if (compressor.option("comparisons")) switch (self.operator) {

96
test/compress/conditionals.js
View File

@@ -797,3 +797,99 @@ no_evaluate: {
}
}
}
equality_conditionals_false: {
options = {
conditionals: false,
sequences: true,
}
input: {
function f(a, b, c) {
console.log(
a == (b ? a : a),
a == (b ? a : c),
a != (b ? a : a),
a != (b ? a : c),
a === (b ? a : a),
a === (b ? a : c),
a !== (b ? a : a),
a !== (b ? a : c)
);
}
f(0, 0, 0);
f(0, true, 0);
f(1, 2, 3);
f(1, null, 3);
f(NaN);
f(NaN, "foo");
}
expect: {
function f(a, b, c) {
console.log(
a == (b ? a : a),
a == (b ? a : c),
a != (b ? a : a),
a != (b ? a : c),
a === (b ? a : a),
a === (b ? a : c),
a !== (b ? a : a),
a !== (b ? a : c)
);
}
f(0, 0, 0),
f(0, true, 0),
f(1, 2, 3),
f(1, null, 3),
f(NaN),
f(NaN, "foo");
}
expect_stdout: true
}
equality_conditionals_true: {
options = {
conditionals: true,
sequences: true,
}
input: {
function f(a, b, c) {
console.log(
a == (b ? a : a),
a == (b ? a : c),
a != (b ? a : a),
a != (b ? a : c),
a === (b ? a : a),
a === (b ? a : c),
a !== (b ? a : a),
a !== (b ? a : c)
);
}
f(0, 0, 0);
f(0, true, 0);
f(1, 2, 3);
f(1, null, 3);
f(NaN);
f(NaN, "foo");
}
expect: {
function f(a, b, c) {
console.log(
(b, a == a),
a == (b ? a : c),
(b, a != a),
a != (b ? a : c),
(b, a === a),
a === (b ? a : c),
(b, a !== a),
a !== (b ? a : c)
);
}
f(0, 0, 0),
f(0, true, 0),
f(1, 2, 3),
f(1, null, 3),
f(NaN),
f(NaN, "foo");
}
expect_stdout: true
}