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Merge pull request #735 from kzc/master

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optimizations for && and || where left side is constant expression
This commit is contained in:
Mihai Bazon
2015-07-20 09:58:01 +03:00
parent 85a5fc0aeb 9d398d999c
commit 63fb2d5a44
2 changed files with 188 additions and 0 deletions
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28
lib/compress.js
View File

@@ -2104,6 +2104,34 @@ merge(Compressor.prototype, {
}
break;
}
if (compressor.option("conditionals")) {
if (self.operator == "&&") {
var ll = self.left.evaluate(compressor);
var rr = self.right.evaluate(compressor);
if (ll.length > 1) {
if (ll[1]) {
compressor.warn("Condition left of && always true [{file}:{line},{col}]", self.start);
return rr[0];
} else {
compressor.warn("Condition left of && always false [{file}:{line},{col}]", self.start);
return ll[0];
}
}
}
else if (self.operator == "||") {
var ll = self.left.evaluate(compressor);
var rr = self.right.evaluate(compressor);
if (ll.length > 1) {
if (ll[1]) {
compressor.warn("Condition left of || always true [{file}:{line},{col}]", self.start);
return ll[0];
} else {
compressor.warn("Condition left of || always false [{file}:{line},{col}]", self.start);
return rr[0];
}
}
}
}
if (compressor.option("booleans") && compressor.in_boolean_context()) switch (self.operator) {
case "&&":
var ll = self.left.evaluate(compressor);

160
test/compress/conditionals.js
View File

@@ -384,3 +384,163 @@ cond_8: {
a = condition ? 1 : 0;
}
}
conditional_and: {
options = {
conditionals: true,
evaluate : true
};
input: {
var a;
// compress these
a = true && condition;
a = 1 && console.log("a");
a = 2 * 3 && 2 * condition;
a = 5 == 5 && condition + 3;
a = "string" && 4 - condition;
a = 5 + "" && condition / 5;
a = -4.5 && 6 << condition;
a = 6 && 7;
a = false && condition;
a = NaN && console.log("b");
a = 0 && console.log("c");
a = undefined && 2 * condition;
a = null && condition + 3;
a = 2 * 3 - 6 && 4 - condition;
a = 10 == 7 && condition / 5;
a = !"string" && 6 % condition;
a = 0 && 7;
// don't compress these
a = condition && true;
a = console.log("a") && 2;
a = 4 - condition && "string";
a = 6 << condition && -4.5;
a = condition && false;
a = console.log("b") && NaN;
a = console.log("c") && 0;
a = 2 * condition && undefined;
a = condition + 3 && null;
}
expect: {
var a;
a = condition;
a = console.log("a");
a = 2 * condition;
a = condition + 3;
a = 4 - condition;
a = condition / 5;
a = 6 << condition;
a = 7;
a = false;
a = NaN;
a = 0;
a = void 0;
a = null;
a = 0;
a = false;
a = false;
a = 0;
a = condition && true;
a = console.log("a") && 2;
a = 4 - condition && "string";
a = 6 << condition && -4.5;
a = condition && false;
a = console.log("b") && NaN;
a = console.log("c") && 0;
a = 2 * condition && void 0;
a = condition + 3 && null;
}
}
conditional_or: {
options = {
conditionals: true,
evaluate : true
};
input: {
var a;
// compress these
a = true || condition;
a = 1 || console.log("a");
a = 2 * 3 || 2 * condition;
a = 5 == 5 || condition + 3;
a = "string" || 4 - condition;
a = 5 + "" || condition / 5;
a = -4.5 || 6 << condition;
a = 6 || 7;
a = false || condition;
a = 0 || console.log("b");
a = NaN || console.log("c");
a = undefined || 2 * condition;
a = null || condition + 3;
a = 2 * 3 - 6 || 4 - condition;
a = 10 == 7 || condition / 5;
a = !"string" || 6 % condition;
a = null || 7;
a = console.log(undefined && condition || null);
a = console.log(undefined || condition && null);
// don't compress these
a = condition || true;
a = console.log("a") || 2;
a = 4 - condition || "string";
a = 6 << condition || -4.5;
a = condition || false;
a = console.log("b") || NaN;
a = console.log("c") || 0;
a = 2 * condition || undefined;
a = condition + 3 || null;
}
expect: {
var a;
a = true;
a = 1;
a = 6;
a = true;
a = "string";
a = "5";
a = -4.5;
a = 6;
a = condition;
a = console.log("b");
a = console.log("c");
a = 2 * condition;
a = condition + 3;
a = 4 - condition;
a = condition / 5;
a = 6 % condition;
a = 7;
a = console.log(null);
a = console.log(condition && null);
a = condition || true;
a = console.log("a") || 2;
a = 4 - condition || "string";
a = 6 << condition || -4.5;
a = condition || false;
a = console.log("b") || NaN;
a = console.log("c") || 0;
a = 2 * condition || void 0;
a = condition + 3 || null;
}
}