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enhance collapse_vars (#3611)

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This commit is contained in:
Alex Lam S.L
2019-11-28 03:57:10 +08:00
committed by GitHub
parent d4b7010678
commit 168ae747ad
2 changed files with 209 additions and 13 deletions
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35
lib/compress.js
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@@ -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);
@@ -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) {
@@ -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;
@@ -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);
@@ -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);
@@ -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);
@@ -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;