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combine rules for binary boolean operations (#1744)

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Alex Lam S.L
2017-03-31 18:47:44 +08:00
committed by GitHub
parent e6b76a4879
commit 1ddc05725d
2 changed files with 41 additions and 53 deletions
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90
lib/compress.js
View File

@@ -3140,42 +3140,7 @@ merge(Compressor.prototype, {
}
break;
}
if (compressor.option("booleans") && compressor.in_boolean_context()) switch (self.operator) {
case "&&":
var ll = self.left.evaluate(compressor);
var rr = self.right.evaluate(compressor);
if (!ll || !rr) {
compressor.warn("Boolean && always false [{file}:{line},{col}]", self.start);
return make_node(AST_Seq, self, {
car: self.left,
cdr: make_node(AST_False, self)
}).optimize(compressor);
}
if (ll !== self.left && ll) {
return self.right.optimize(compressor);
}
if (rr !== self.right && rr) {
return self.left.optimize(compressor);
}
break;
case "||":
var ll = self.left.evaluate(compressor);
var rr = self.right.evaluate(compressor);
if (ll !== self.left && ll || rr !== self.right && rr) {
compressor.warn("Boolean || always true [{file}:{line},{col}]", self.start);
return make_node(AST_Seq, self, {
car: self.left,
cdr: make_node(AST_True, self)
}).optimize(compressor);
}
if (!ll) {
return self.right.optimize(compressor);
}
if (!rr) {
return self.left.optimize(compressor);
}
break;
case "+":
if (compressor.option("booleans") && self.operator == "+" && compressor.in_boolean_context()) {
var ll = self.left.evaluate(compressor);
var rr = self.right.evaluate(compressor);
if (ll && typeof ll == "string") {
@@ -3192,7 +3157,6 @@ merge(Compressor.prototype, {
cdr: make_node(AST_True, self)
}).optimize(compressor);
}
break;
}
if (compressor.option("comparisons") && self.is_boolean()) {
if (!(compressor.parent() instanceof AST_Binary)
@@ -3233,24 +3197,48 @@ merge(Compressor.prototype, {
if (compressor.option("evaluate")) {
switch (self.operator) {
case "&&":
if (self.left.is_constant()) {
if (self.left.constant_value(compressor)) {
compressor.warn("Condition left of && always true [{file}:{line},{col}]", self.start);
return maintain_this_binding(compressor.parent(), self, self.right);
} else {
compressor.warn("Condition left of && always false [{file}:{line},{col}]", self.start);
return maintain_this_binding(compressor.parent(), self, self.left);
var ll = self.left.evaluate(compressor);
if (!ll) {
compressor.warn("Condition left of && always false [{file}:{line},{col}]", self.start);
return maintain_this_binding(compressor.parent(), self, self.left).optimize(compressor);
} else if (ll !== self.left) {
compressor.warn("Condition left of && always true [{file}:{line},{col}]", self.start);
return maintain_this_binding(compressor.parent(), self, self.right).optimize(compressor);
}
if (compressor.option("booleans") && compressor.in_boolean_context()) {
var rr = self.right.evaluate(compressor);
if (!rr) {
compressor.warn("Boolean && always false [{file}:{line},{col}]", self.start);
return make_node(AST_Seq, self, {
car: self.left,
cdr: make_node(AST_False, self)
}).optimize(compressor);
} else if (rr !== self.right) {
compressor.warn("Dropping side-effect-free && in boolean context [{file}:{line},{col}]", self.start);
return self.left.optimize(compressor);
}
}
break;
case "||":
if (self.left.is_constant()) {
if (self.left.constant_value(compressor)) {
compressor.warn("Condition left of || always true [{file}:{line},{col}]", self.start);
return maintain_this_binding(compressor.parent(), self, self.left);
} else {
compressor.warn("Condition left of || always false [{file}:{line},{col}]", self.start);
return maintain_this_binding(compressor.parent(), self, self.right);
var ll = self.left.evaluate(compressor);
if (!ll) {
compressor.warn("Condition left of || always false [{file}:{line},{col}]", self.start);
return maintain_this_binding(compressor.parent(), self, self.right).optimize(compressor);
} else if (ll !== self.left) {
compressor.warn("Condition left of || always true [{file}:{line},{col}]", self.start);
return maintain_this_binding(compressor.parent(), self, self.left).optimize(compressor);
}
if (compressor.option("booleans") && compressor.in_boolean_context()) {
var rr = self.right.evaluate(compressor);
if (!rr) {
compressor.warn("Dropping side-effect-free || in boolean context [{file}:{line},{col}]", self.start);
return self.left.optimize(compressor);
} else if (rr !== self.right) {
compressor.warn("Boolean || always true [{file}:{line},{col}]", self.start);
return make_node(AST_Seq, self, {
car: self.left,
cdr: make_node(AST_True, self)
}).optimize(compressor);
}
}
break;

4
test/compress/issue-1261.js
View File

@@ -154,12 +154,12 @@ should_warn: {
"WARN: Boolean || always true [test/compress/issue-1261.js:129,23]",
"WARN: Dropping __PURE__ call [test/compress/issue-1261.js:129,23]",
"WARN: Condition always true [test/compress/issue-1261.js:129,23]",
"WARN: Boolean || always true [test/compress/issue-1261.js:130,8]",
"WARN: Condition left of || always true [test/compress/issue-1261.js:130,8]",
"WARN: Condition always true [test/compress/issue-1261.js:130,8]",
"WARN: Boolean && always false [test/compress/issue-1261.js:131,23]",
"WARN: Dropping __PURE__ call [test/compress/issue-1261.js:131,23]",
"WARN: Condition always false [test/compress/issue-1261.js:131,23]",
"WARN: Boolean && always false [test/compress/issue-1261.js:132,8]",
"WARN: Condition left of && always false [test/compress/issue-1261.js:132,8]",
"WARN: Condition always false [test/compress/issue-1261.js:132,8]",
"WARN: + in boolean context always true [test/compress/issue-1261.js:133,23]",
"WARN: Dropping __PURE__ call [test/compress/issue-1261.js:133,23]",