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Parse and compress destructuring VarDefs

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This commit is contained in:
Fábio Santos
2015-08-14 00:20:21 +01:00
committed by Richard van Velzen
parent 824ecfb8a2
commit c44c2d6c21
7 changed files with 105 additions and 8 deletions
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5
lib/ast.js
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@@ -665,9 +665,12 @@ var AST_Const = DEFNODE("Const", null, {
var AST_VarDef = DEFNODE("VarDef", "name value", {
$documentation: "A variable declaration; only appears in a AST_Definitions node",
$propdoc: {
name: "[AST_SymbolVar|AST_SymbolConst] name of the variable",
name: "[AST_SymbolVar|AST_SymbolConst|AST_Destructuring] name of the variable",
value: "[AST_Node?] initializer, or null of there's no initializer"
},
is_destructuring: function() {
return this.name instanceof AST_Destructuring;
},
_walk: function(visitor) {
return visitor._visit(this, function(){
this.name._walk(visitor);

15
lib/compress.js
View File

@@ -1056,6 +1056,7 @@ merge(Compressor.prototype, {
}
if (node instanceof AST_Definitions && scope === self) {
node.definitions.forEach(function(def){
if (def.is_destructuring()) return; /* Destructurings are type assertions! */
if (def.value) {
initializations.add(def.name.name, def.value);
if (def.value.has_side_effects(compressor)) {
@@ -1142,6 +1143,7 @@ merge(Compressor.prototype, {
}
if (node instanceof AST_Definitions && !(tt.parent() instanceof AST_ForIn)) {
var def = node.definitions.filter(function(def){
if (def.is_destructuring()) return true;
if (member(def.name.definition(), in_use)) return true;
var w = {
name : def.name.name,
@@ -1262,6 +1264,7 @@ merge(Compressor.prototype, {
}
if (node instanceof AST_Var && hoist_vars) {
node.definitions.forEach(function(def){
if (def.is_destructuring()) { return; }
vars.set(def.name.name, def);
++vars_found;
});
@@ -1702,13 +1705,23 @@ merge(Compressor.prototype, {
AST_Definitions.DEFMETHOD("to_assignments", function(){
var assignments = this.definitions.reduce(function(a, def){
if (def.value) {
if (def.value && !def.is_destructuring()) {
var name = make_node(AST_SymbolRef, def.name, def.name);
a.push(make_node(AST_Assign, def, {
operator : "=",
left : name,
right : def.value
}));
} else if (def.value) {
// Because it's a destructuring, do not turn into an assignment.
var varDef = make_node(AST_VarDef, def, {
name: def.name,
value: def.value
});
var var_ = make_node(AST_Var, def, {
definitions: [ varDef ]
});
a.push(var_);
}
return a;
}, []);

33
lib/parse.js
View File

@@ -1180,13 +1180,24 @@ function parse($TEXT, options) {
function vardefs(no_in, in_const) {
var a = [];
var def;
for (;;) {
a.push(new AST_VarDef({
start : S.token,
name : as_symbol(in_const ? AST_SymbolConst : AST_SymbolVar),
value : is("operator", "=") ? (next(), expression(false, no_in)) : null,
end : prev()
}));
if (is("punc", "{") || is("punc", "[")) {
def = new AST_VarDef({
start: S.token,
name: destructuring_(),
value: (expect_token("operator", "="), expression(false, no_in)),
end: prev()
});
} else {
def = new AST_VarDef({
start : S.token,
name : as_symbol(in_const ? AST_SymbolConst : AST_SymbolVar),
value : is("operator", "=") ? (next(), expression(false, no_in)) : null,
end : prev()
})
}
a.push(def);
if (!is("punc", ","))
break;
next();
@@ -1194,6 +1205,16 @@ function parse($TEXT, options) {
return a;
};
var destructuring_ = embed_tokens(function () {
var is_array = is("punc", "[");
var closing = is_array ? ']' : '}';
next()
return new AST_Destructuring({
names: expr_list(closing),
is_array: is_array
})
});
var var_ = function(no_in) {
return new AST_Var({
start : prev(),