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enhance booleans & evaluate (#5364)
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@alexlamsl
alexlamsl committed Feb 20, 2022
1 parent 212ce46 commit d5afe16
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Showing 3 changed files with 70 additions and 43 deletions.
73 changes: 30 additions & 43 deletions lib/compress.js
View file
Expand Up @@ -11134,21 +11134,17 @@ Compressor.prototype.compress = function(node) {
}
if (in_bool) switch (self.operator) {
case "+":
var ll = self.left.evaluate(compressor);
var rr = self.right.evaluate(compressor);
if (ll && typeof ll == "string") {
var ev = self.left.evaluate(compressor, true);
if (ev && typeof ev == "string" || (ev = self.right.evaluate(compressor, true)) && typeof ev == "string") {
AST_Node.warn("+ in boolean context always true [{file}:{line},{col}]", self.start);
return make_sequence(self, [
self.right,
make_node(AST_True, self)
]).optimize(compressor);
}
if (rr && typeof rr == "string") {
AST_Node.warn("+ in boolean context always true [{file}:{line},{col}]", self.start);
return make_sequence(self, [
self.left,
make_node(AST_True, self)
]).optimize(compressor);
var exprs = [];
if (self.left.evaluate(compressor) instanceof AST_Node) exprs.push(self.left);
if (self.right.evaluate(compressor) instanceof AST_Node) exprs.push(self.right);
if (exprs.length < 2) {
exprs.push(make_node(AST_True, self));
return make_sequence(self, exprs).optimize(compressor);
}
self.truthy = true;
}
break;
case "==":
Expand Down Expand Up @@ -11231,20 +11227,15 @@ Compressor.prototype.compress = function(node) {
AST_Node.warn("Condition left of && always true [{file}:{line},{col}]", self.start);
return make_sequence(self, [ self.left, self.right ]).optimize(compressor);
}
var rr = self.right.evaluate(compressor);
if (!rr) {
if (in_bool) {
if (!self.right.evaluate(compressor, true)) {
if (in_bool && !(self.right.evaluate(compressor) instanceof AST_Node)) {
AST_Node.warn("Boolean && always false [{file}:{line},{col}]", self.start);
return make_sequence(self, [
self.left,
make_node(AST_False, self)
]).optimize(compressor);
return make_sequence(self, [ self.left, make_node(AST_False, self) ]).optimize(compressor);
} else self.falsy = true;
} else if (!(rr instanceof AST_Node)) {
if (in_bool || parent.operator == "&&" && parent.left === compressor.self()) {
AST_Node.warn("Dropping side-effect-free && [{file}:{line},{col}]", self.start);
return self.left.optimize(compressor);
}
} else if ((in_bool || parent.operator == "&&" && parent.left === compressor.self())
&& !(self.right.evaluate(compressor) instanceof AST_Node)) {
AST_Node.warn("Dropping side-effect-free && [{file}:{line},{col}]", self.start);
return self.left.optimize(compressor);
}
// (x || false) && y ---> x ? y : false
if (self.left.operator == "||") {
Expand Down Expand Up @@ -11279,25 +11270,21 @@ Compressor.prototype.compress = function(node) {
});
return maintain_this_binding(compressor, parent, compressor.self(), self.left).optimize(compressor);
}
var rr = self.right.evaluate(compressor);
if (!rr) {
if (in_bool || parent.operator == "||" && parent.left === compressor.self()) {
AST_Node.warn("Dropping side-effect-free {operator} [{file}:{line},{col}]", {
operator: self.operator,
file: self.start.file,
line: self.start.line,
col: self.start.col,
});
return self.left.optimize(compressor);
}
} else if (!nullish && !(rr instanceof AST_Node)) {
if (in_bool) {
var rr;
if (!nullish && (rr = self.right.evaluate(compressor, true)) && !(rr instanceof AST_Node)) {
if (in_bool && !(self.right.evaluate(compressor) instanceof AST_Node)) {
AST_Node.warn("Boolean || always true [{file}:{line},{col}]", self.start);
return make_sequence(self, [
self.left,
make_node(AST_True, self)
]).optimize(compressor);
return make_sequence(self, [ self.left, make_node(AST_True, self) ]).optimize(compressor);
} else self.truthy = true;
} else if ((in_bool || parent.operator == "||" && parent.left === compressor.self())
&& !self.right.evaluate(compressor)) {
AST_Node.warn("Dropping side-effect-free {operator} [{file}:{line},{col}]", {
operator: self.operator,
file: self.start.file,
line: self.start.line,
col: self.start.col,
});
return self.left.optimize(compressor);
}
// x && true || y ---> x ? true : y
if (!nullish && self.left.operator == "&&") {
Expand Down
21 changes: 21 additions & 0 deletions test/compress/booleans.js
View file
Expand Up @@ -427,6 +427,27 @@ negated_if: {
expect_stdout: "PASS"
}

concat_truthy: {
options = {
booleans: true,
evaluate: true,
}
input: {
console.log("foo") + (console.log("bar"), "baz") || console.log("moo");
}
expect: {
console.log("foo") + (console.log("bar"), "baz");
}
expect_stdout: [
"foo",
"bar",
]
expect_warnings: [
"WARN: + in boolean context always true [test/compress/booleans.js:1,8]",
"WARN: Condition left of || always true [test/compress/booleans.js:1,8]",
]
}

issue_3465_1: {
options = {
booleans: true,
Expand Down
19 changes: 19 additions & 0 deletions test/compress/evaluate.js
View file
Expand Up @@ -888,6 +888,25 @@ unsafe_charAt_noop: {
expect_stdout: "f n"
}

chained_side_effects: {
options = {
evaluate: true,
}
input: {
console.log("foo") || (console.log("bar"), "baz") || console.log("moo");
}
expect: {
console.log("foo") || (console.log("bar"), "baz");
}
expect_stdout: [
"foo",
"bar",
]
expect_warnings: [
"WARN: Condition left of || always true [test/compress/evaluate.js:1,8]",
]
}

issue_1649: {
options = {
evaluate: true,
Expand Down

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