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introduce functions (#3360)
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`var f = function() {};` => `function f() {}`
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@alexlamsl
alexlamsl committed Apr 15, 2019
1 parent a57b069 commit 5172ba5
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Showing 7 changed files with 268 additions and 46 deletions.
3 changes: 3 additions & 0 deletions README.md
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Expand Up @@ -636,6 +636,9 @@ If you're using the `X-SourceMap` header instead, you can just omit `sourceMap.u
- `expression` (default: `false`) -- Pass `true` to preserve completion values
from terminal statements without `return`, e.g. in bookmarklets.

- `functions` (default: `true`) -- convert declarations from `var`to `function`
whenever possible.

- `global_defs` (default: `{}`) -- see [conditional compilation](#conditional-compilation)

- `hoist_funs` (default: `false`) -- hoist function declarations
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84 changes: 46 additions & 38 deletions lib/compress.js
View file
Expand Up @@ -60,6 +60,7 @@ function Compressor(options, false_by_default) {
drop_debugger : !false_by_default,
evaluate : !false_by_default,
expression : false,
functions : !false_by_default,
global_defs : false,
hoist_funs : false,
hoist_props : !false_by_default,
Expand Down Expand Up @@ -150,7 +151,7 @@ Compressor.prototype = new TreeTransformer;
merge(Compressor.prototype, {
option: function(key) { return this.options[key] },
exposed: function(def) {
if (def.global) for (var i = 0, len = def.orig.length; i < len; i++)
if (def.global) for (var i = 0; i < def.orig.length; i++)
if (!this.toplevel[def.orig[i] instanceof AST_SymbolDefun ? "funcs" : "vars"])
return true;
return false;
Expand Down Expand Up @@ -1241,7 +1242,7 @@ merge(Compressor.prototype, {
// Scan case expressions first in a switch statement
if (node instanceof AST_Switch) {
node.expression = node.expression.transform(scanner);
for (var i = 0, len = node.body.length; !abort && i < len; i++) {
for (var i = 0; !abort && i < node.body.length; i++) {
var branch = node.body[i];
if (branch instanceof AST_Case) {
if (!hit) {
Expand Down Expand Up @@ -1887,7 +1888,7 @@ merge(Compressor.prototype, {
}

function next_index(i) {
for (var j = i + 1, len = statements.length; j < len; j++) {
for (var j = i + 1; j < statements.length; j++) {
var stat = statements[j];
if (!(stat instanceof AST_Var && declarations_only(stat))) {
break;
Expand Down Expand Up @@ -1978,7 +1979,7 @@ merge(Compressor.prototype, {
function to_simple_statement(block, decls) {
if (!(block instanceof AST_BlockStatement)) return block;
var stat = null;
for (var i = 0, len = block.body.length; i < len; i++) {
for (var i = 0; i < block.body.length; i++) {
var line = block.body[i];
if (line instanceof AST_Var && declarations_only(line)) {
decls.push(line);
Expand Down Expand Up @@ -2118,7 +2119,7 @@ merge(Compressor.prototype, {

function join_consecutive_vars(statements) {
var defs;
for (var i = 0, j = -1, len = statements.length; i < len; i++) {
for (var i = 0, j = -1; i < statements.length; i++) {
var stat = statements[i];
var prev = statements[j];
if (stat instanceof AST_Definitions) {
Expand Down Expand Up @@ -2719,7 +2720,7 @@ merge(Compressor.prototype, {
def(AST_Array, function(compressor, cached, depth) {
if (compressor.option("unsafe")) {
var elements = [];
for (var i = 0, len = this.elements.length; i < len; i++) {
for (var i = 0; i < this.elements.length; i++) {
var element = this.elements[i];
var value = element._eval(compressor, cached, depth);
if (element === value) return this;
Expand All @@ -2732,7 +2733,7 @@ merge(Compressor.prototype, {
def(AST_Object, function(compressor, cached, depth) {
if (compressor.option("unsafe")) {
var val = {};
for (var i = 0, len = this.properties.length; i < len; i++) {
for (var i = 0; i < this.properties.length; i++) {
var prop = this.properties[i];
var key = prop.key;
if (key instanceof AST_Symbol) {
Expand Down Expand Up @@ -2927,7 +2928,7 @@ merge(Compressor.prototype, {
if (!native_fn || !native_fn[key]) return this;
}
var args = [];
for (var i = 0, len = this.args.length; i < len; i++) {
for (var i = 0; i < this.args.length; i++) {
var arg = this.args[i];
var value = arg._eval(compressor, cached, depth);
if (arg === value) return this;
Expand Down Expand Up @@ -3463,9 +3464,7 @@ merge(Compressor.prototype, {
if (node instanceof AST_Definitions && scope === self) {
node.definitions.forEach(function(def) {
var node_def = def.name.definition();
if (def.name instanceof AST_SymbolVar) {
var_defs_by_id.add(node_def.id, def);
}
var_defs_by_id.add(node_def.id, def);
if (!drop_vars) {
if (!(node_def.id in in_use_ids)) {
in_use_ids[node_def.id] = true;
Expand Down Expand Up @@ -3572,29 +3571,40 @@ merge(Compressor.prototype, {
if (def.value && sym.id in fixed_ids && fixed_ids[sym.id] !== def) {
def.value = def.value.drop_side_effect_free(compressor);
}
if (def.name instanceof AST_SymbolVar) {
var var_defs = var_defs_by_id.get(sym.id);
if (var_defs.length > 1 && (!def.value || sym.orig.indexOf(def.name) > sym.eliminated)) {
compressor.warn("Dropping duplicated definition of variable {name} [{file}:{line},{col}]", template(def.name));
if (def.value) {
var ref = make_node(AST_SymbolRef, def.name, def.name);
sym.references.push(ref);
var assign = make_node(AST_Assign, def, {
operator: "=",
left: ref,
right: def.value
});
if (fixed_ids[sym.id] === def) {
fixed_ids[sym.id] = assign;
}
side_effects.push(assign.transform(tt));
var var_defs = var_defs_by_id.get(sym.id);
if (var_defs.length > 1 && (!def.value || sym.orig.indexOf(def.name) > sym.eliminated)) {
compressor.warn("Dropping duplicated definition of variable {name} [{file}:{line},{col}]", template(def.name));
if (def.value) {
var ref = make_node(AST_SymbolRef, def.name, def.name);
sym.references.push(ref);
var assign = make_node(AST_Assign, def, {
operator: "=",
left: ref,
right: def.value
});
if (fixed_ids[sym.id] === def) {
fixed_ids[sym.id] = assign;
}
remove(var_defs, def);
sym.eliminated++;
return;
side_effects.push(assign.transform(tt));
}
remove(var_defs, def);
sym.eliminated++;
return;
}
if (def.value) {
if (!def.value) {
head.push(def);
} else if (compressor.option("functions")
&& def.value === def.name.fixed_value()
&& def.value instanceof AST_Function
&& !def.value.name
&& !def.value.variables.get(def.name.name)
&& (!compressor.has_directive("use strict") || parent instanceof AST_Scope)) {
compressor.warn("Declaring {name} as function [{file}:{line},{col}]", template(def.name));
var defun = make_node(AST_Defun, def, def.value);
defun.name = make_node(AST_SymbolDefun, def.name, def.name);
self.def_function(defun.name);
body.push(defun);
} else {
if (side_effects.length > 0) {
if (tail.length > 0) {
side_effects.push(def.value);
Expand All @@ -3607,8 +3617,6 @@ merge(Compressor.prototype, {
side_effects = [];
}
tail.push(def);
} else {
head.push(def);
}
} else if (sym.orig[0] instanceof AST_SymbolCatch) {
var value = def.value && def.value.drop_side_effect_free(compressor);
Expand Down Expand Up @@ -4669,7 +4677,7 @@ merge(Compressor.prototype, {
&& !fn.uses_arguments
&& !fn.pinned()) {
var pos = 0, last = 0;
for (var i = 0, len = self.args.length; i < len; i++) {
for (var i = 0; i < self.args.length; i++) {
var trim = i >= fn.argnames.length;
if (trim || fn.argnames[i].__unused) {
var node = self.args[i].drop_side_effect_free(compressor);
Expand Down Expand Up @@ -5047,7 +5055,7 @@ merge(Compressor.prototype, {
}

function can_inject_args(catches, safe_to_inject) {
for (var i = 0, len = fn.argnames.length; i < len; i++) {
for (var i = 0; i < fn.argnames.length; i++) {
var arg = fn.argnames[i];
if (arg.__unused) continue;
if (!safe_to_inject
Expand All @@ -5062,7 +5070,7 @@ merge(Compressor.prototype, {
}

function can_inject_vars(catches, safe_to_inject) {
for (var i = 0, len = fn.body.length; i < len; i++) {
for (var i = 0; i < fn.body.length; i++) {
var stat = fn.body[i];
if (!(stat instanceof AST_Var)) continue;
if (!safe_to_inject) return false;
Expand Down Expand Up @@ -5142,10 +5150,10 @@ merge(Compressor.prototype, {

function flatten_vars(decls, expressions) {
var pos = expressions.length;
for (var i = 0, lines = fn.body.length; i < lines; i++) {
for (var i = 0; i < fn.body.length; i++) {
var stat = fn.body[i];
if (!(stat instanceof AST_Var)) continue;
for (var j = 0, defs = stat.definitions.length; j < defs; j++) {
for (var j = 0; j < stat.definitions.length; j++) {
var var_def = stat.definitions[j];
var name = var_def.name;
var redef = name.definition().redefined();
Expand Down
2 changes: 1 addition & 1 deletion lib/output.js
View file
Expand Up @@ -123,7 +123,7 @@ function OutputStream(options) {
});
} : function(str) {
var s = "";
for (var i = 0, len = str.length; i < len; i++) {
for (var i = 0; i < str.length; i++) {
if (is_surrogate_pair_head(str[i]) && !is_surrogate_pair_tail(str[i + 1])
|| is_surrogate_pair_tail(str[i]) && !is_surrogate_pair_head(str[i - 1])) {
s += "\\u" + str.charCodeAt(i).toString(16);
Expand Down
6 changes: 2 additions & 4 deletions lib/parse.js
View file
Expand Up @@ -272,10 +272,8 @@ function tokenizer($TEXT, filename, html5_comments, shebang) {

function find_eol() {
var text = S.text;
for (var i = S.pos, n = S.text.length; i < n; ++i) {
var ch = text[i];
if (NEWLINE_CHARS[ch])
return i;
for (var i = S.pos; i < S.text.length; ++i) {
if (NEWLINE_CHARS[text[i]]) return i;
}
return -1;
}
Expand Down
4 changes: 2 additions & 2 deletions lib/scope.js
View file
Expand Up @@ -333,7 +333,7 @@ function next_mangled_name(scope, options, def) {
} while (scope = scope.parent_scope);
});
var name;
for (var i = 0, len = holes.length; i < len; i++) {
for (var i = 0; i < holes.length; i++) {
name = base54(holes[i]);
if (names[name]) continue;
holes.splice(i, 1);
Expand Down Expand Up @@ -555,7 +555,7 @@ var base54 = (function() {
var freq = Object.create(null);
function init(chars) {
var array = [];
for (var i = 0, len = chars.length; i < len; i++) {
for (var i = 0; i < chars.length; i++) {
var ch = chars[i];
array.push(ch);
freq[ch] = -1e-2 * i;
Expand Down

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