diff options
| author | Alex Lam S.L <alexlamsl@gmail.com> | 2019-12-31 23:39:24 +0800 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2019-12-31 23:39:24 +0800 |
| commit | d83d3d741ac8ea41a3776c9ca8d60e752180d420 (patch) | |
| tree | 8fcc54acf1987c051dc51c186a0f0f77fab1966a /lib | |
| parent | 99ac73a635d641935331e71d519c24297b50dd32 (diff) | |
| download | tracifyjs-d83d3d741ac8ea41a3776c9ca8d60e752180d420.tar.gz tracifyjs-d83d3d741ac8ea41a3776c9ca8d60e752180d420.zip | |
enhance `unused` (#3662)
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/compress.js | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/lib/compress.js b/lib/compress.js index 38d09068..2bbd9704 100644 --- a/lib/compress.js +++ b/lib/compress.js @@ -3879,7 +3879,7 @@ merge(Compressor.prototype, { }); return true; } - return scan_ref_scoped(node, descend); + return scan_ref_scoped(node, descend, true); }); self.walk(tw); // pass 2: for every used symbol we need to walk its @@ -3913,6 +3913,11 @@ merge(Compressor.prototype, { if (node instanceof AST_Assign) { if (!in_use || node.left === sym && def.id in fixed_ids && fixed_ids[def.id] !== node) { value = get_rhs(node); + if (node.write_only) { + value = value.drop_side_effect_free(compressor) || make_node(AST_Number, node, { + value: 0 + }); + } } } else if (!in_use) { value = make_node(AST_Number, node, { @@ -4182,7 +4187,7 @@ merge(Compressor.prototype, { return rhs.right.has_side_effects(compressor) ? rhs : rhs.right; } - function scan_ref_scoped(node, descend) { + function scan_ref_scoped(node, descend, init) { var node_def, props = [], sym = assign_as_unused(node, props); if (sym && self.variables.get(sym.name) === (node_def = sym.definition())) { props.forEach(function(prop) { @@ -4191,7 +4196,11 @@ merge(Compressor.prototype, { if (node instanceof AST_Assign) { if (node.write_only === "p" && node.right.may_throw_on_access(compressor)) return; var right = get_rhs(node); - right.walk(tw); + if (init && node.write_only && node_def.scope === self && !right.has_side_effects(compressor)) { + initializations.add(node_def.id, right); + } else { + right.walk(tw); + } if (node.left === sym) { if (!node_def.chained && sym.fixed_value(true) === right) { fixed_ids[node_def.id] = node; |