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enhance collapse_vars (#3611)
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@alexlamsl
alexlamsl committed Nov 27, 2019
1 parent d4b7010 commit 168ae74
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Showing 2 changed files with 209 additions and 13 deletions.
35 changes: 25 additions & 10 deletions lib/compress.js
View file
Expand Up @@ -1415,7 +1415,9 @@ merge(Compressor.prototype, {

function extract_candidates(expr) {
hit_stack.push(expr);
if (expr instanceof AST_Assign) {
if (expr instanceof AST_Array) {
expr.elements.forEach(extract_candidates);
} else if (expr instanceof AST_Assign) {
candidates.push(hit_stack.slice());
extract_candidates(expr.left);
extract_candidates(expr.right);
Expand Down Expand Up @@ -1462,6 +1464,14 @@ merge(Compressor.prototype, {
if (expr.alternative && !(expr.alternative instanceof AST_Block)) {
extract_candidates(expr.alternative);
}
} else if (expr instanceof AST_Object) {
expr.properties.forEach(function(prop) {
if (prop instanceof AST_ObjectKeyVal) {
hit_stack.push(prop);
extract_candidates(prop.value);
hit_stack.pop();
}
});
} else if (expr instanceof AST_Sequence) {
expr.expressions.forEach(extract_candidates);
} else if (expr instanceof AST_SimpleStatement) {
Expand Down Expand Up @@ -1492,6 +1502,7 @@ merge(Compressor.prototype, {

function find_stop(node, level) {
var parent = scanner.parent(level);
if (parent instanceof AST_Array) return node;
if (parent instanceof AST_Assign) return node;
if (parent instanceof AST_Binary) return node;
if (parent instanceof AST_Call) return node;
Expand All @@ -1501,6 +1512,7 @@ merge(Compressor.prototype, {
if (parent instanceof AST_Exit) return node;
if (parent instanceof AST_If) return node;
if (parent instanceof AST_IterationStatement) return node;
if (parent instanceof AST_ObjectKeyVal) return node;
if (parent instanceof AST_PropAccess) return node;
if (parent instanceof AST_Sequence) {
return (parent.tail_node() === node ? find_stop : find_stop_unused)(parent, level + 1);
Expand All @@ -1516,6 +1528,7 @@ merge(Compressor.prototype, {
var parent = scanner.parent(level);
if (is_last_node(node, parent)) return node;
if (in_conditional(node, parent)) return node;
if (parent instanceof AST_Array) return find_stop_unused(parent, level + 1);
if (parent instanceof AST_Assign) return find_stop_unused(parent, level + 1);
if (parent instanceof AST_Binary) return find_stop_unused(parent, level + 1);
if (parent instanceof AST_Call) return find_stop_unused(parent, level + 1);
Expand All @@ -1525,6 +1538,7 @@ merge(Compressor.prototype, {
if (parent instanceof AST_Exit) return find_stop_unused(parent, level + 1);
if (parent instanceof AST_If) return find_stop_unused(parent, level + 1);
if (parent instanceof AST_IterationStatement) return node;
if (parent instanceof AST_ObjectKeyVal) return find_stop_unused(scanner.parent(level + 1), level + 2);
if (parent instanceof AST_PropAccess) {
var exp = parent.expression;
if (exp === node) return find_stop_unused(parent, level + 1);
Expand Down Expand Up @@ -1668,20 +1682,21 @@ merge(Compressor.prototype, {
var found = false;
return statements[stat_index].transform(new TreeTransformer(function(node, descend, in_list) {
if (found) return node;
if (node instanceof AST_Scope) return node;
if (node !== expr && node.body !== expr) return;
found = true;
if (node instanceof AST_VarDef) {
found = true;
node.value = null;
return node;
}
if (in_list) {
found = true;
return MAP.skip;
}
if (!this.parent()) {
found = true;
return null;
}
var parent = this.parent();
if (!parent) return in_list ? MAP.skip : null;
if (parent instanceof AST_Sequence) return MAP.skip;
var value = expr;
do {
value = get_rvalue(value);
} while (value instanceof AST_Assign);
return value;
}, function(node) {
if (node instanceof AST_Sequence) switch (node.expressions.length) {
case 0: return null;
Expand Down
187 changes: 184 additions & 3 deletions test/compress/collapse_vars.js
View file
Expand Up @@ -669,7 +669,7 @@ collapse_vars_throw: {
expect_stdout: "13"
}

collapse_vars_switch: {
collapse_vars_switch_1: {
options = {
booleans: true,
collapse_vars: true,
Expand Down Expand Up @@ -721,6 +721,31 @@ collapse_vars_switch: {
}
}

collapse_vars_switch_2: {
options = {
collapse_vars: true,
}
input: {
var c = 0;
(function(b) {
switch (b && [ b = 0, (c++, 0) ]) {
case c = 1 + c:
}
})();
console.log(c);
}
expect: {
var c = 0;
(function(b) {
switch (b && [ b = 0, (c++, 0) ]) {
case c = 1 + c:
}
})();
console.log(c);
}
expect_stdout: "1"
}

collapse_vars_assignment: {
options = {
booleans: true,
Expand Down Expand Up @@ -1234,7 +1259,7 @@ collapse_vars_try: {
}
}

collapse_vars_array: {
collapse_vars_array_1: {
options = {
booleans: true,
collapse_vars: true,
Expand Down Expand Up @@ -1280,7 +1305,58 @@ collapse_vars_array: {
}
}

collapse_vars_object: {
collapse_vars_array_2: {
options = {
collapse_vars: true,
unused: true,
}
input: {
function f(a) {
var b;
return [ (b = a, b.g()) ];
}
console.log(f({
g: function() {
return "PASS";
}
})[0]);
}
expect: {
function f(a) {
return [ a.g() ];
}
console.log(f({
g: function() {
return "PASS";
}
})[0]);
}
expect_stdout: "PASS"
}

collapse_vars_array_3: {
options = {
collapse_vars: true,
unused: true,
}
input: {
function f(a) {
var b;
return [ b = a, b, b ];
}
console.log(f().length);
}
expect: {
function f(a) {
var b;
return [ b = a, b, b ];
}
console.log(f().length);
}
expect_stdout: "3"
}

collapse_vars_object_1: {
options = {
booleans: true,
collapse_vars: true,
Expand Down Expand Up @@ -1360,6 +1436,69 @@ collapse_vars_object: {
}
}

collapse_vars_object_2: {
options = {
collapse_vars: true,
unused: true,
}
input: {
function f(a) {
var b;
return {
p: (b = a, b.g())
};
}
console.log(f({
g: function() {
return "PASS";
}
}).p);
}
expect: {
function f(a) {
return {
p: a.g()
};
}
console.log(f({
g: function() {
return "PASS";
}
}).p);
}
expect_stdout: "PASS"
}

collapse_vars_object_3: {
options = {
collapse_vars: true,
unused: true,
}
input: {
function f(a) {
var b;
return {
p: b = a,
q: b,
r: b,
};
}
console.log(f("PASS").r);
}
expect: {
function f(a) {
var b;
return {
p: b = a,
q: b,
r: b,
};
}
console.log(f("PASS").r);
}
expect_stdout: "PASS"
}

collapse_vars_eval_and_with: {
options = {
booleans: true,
Expand Down Expand Up @@ -6624,3 +6763,45 @@ local_value_replacement: {
}
expect_stdout: "PASS"
}

array_in_object_1: {
options = {
collapse_vars: true,
}
input: {
var a = 2;
console.log({
p: [ a, a-- ],
q: a,
}.q, a);
}
expect: {
var a = 2;
console.log({
p: [ a, a-- ],
q: a,
}.q, a);
}
expect_stdout: "1 1"
}

array_in_object_2: {
options = {
collapse_vars: true,
}
input: {
var a = 2;
console.log({
p: [ a, (a--, 42) ],
q: a,
}.q, a);
}
expect: {
var a = 2;
console.log({
p: [ a, 42 ],
q: --a,
}.q, a);
}
expect_stdout: "1 1"
}

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