evanw/esbuild v0.14.47

on GitHub

Make global names more compact when ||= is available (#2331)

With this release, the code esbuild generates for the --global-name= setting is now slightly shorter when you don't configure esbuild such that the ||= operator is unsupported (e.g. with --target=chrome80 or --supported:logical-assignment=false):

// Original code
exports.foo = 123

// Old output (with --format=iife --global-name=foo.bar.baz --minify)
var foo=foo||{};foo.bar=foo.bar||{};foo.bar.baz=(()=>{var b=(a,o)=>()=>(o||a((o={exports:{}}).exports,o),o.exports);var c=b(f=>{f.foo=123});return c();})();

// New output (with --format=iife --global-name=foo.bar.baz --minify)
var foo;((foo||={}).bar||={}).baz=(()=>{var b=(a,o)=>()=>(o||a((o={exports:{}}).exports,o),o.exports);var c=b(f=>{f.foo=123});return c();})();

Fix --mangle-quoted=false with --minify-syntax=true

If property mangling is active and --mangle-quoted is disabled, quoted properties are supposed to be preserved. However, there was a case when this didn't happen if --minify-syntax was enabled, since that internally transforms x['y'] into x.y to reduce code size. This issue has been fixed:

// Original code
x.foo = x['bar'] = { foo: y, 'bar': z }

// Old output (with --mangle-props=. --mangle-quoted=false --minify-syntax=true)
x.a = x.b = { a: y, bar: z };

// New output (with --mangle-props=. --mangle-quoted=false --minify-syntax=true)
x.a = x.bar = { a: y, bar: z };

Notice how the property foo is always used unquoted but the property bar is always used quoted, so foo should be consistently mangled while bar should be consistently not mangled.

Fix a minification bug regarding this and property initializers

When minification is enabled, esbuild attempts to inline the initializers of variables that have only been used once into the start of the following expression to reduce code size. However, there was a bug where this transformation could change the value of this when the initializer is a property access and the start of the following expression is a call expression. This release fixes the bug:

// Original code
function foo(obj) {
  let fn = obj.prop;
  fn();
}

// Old output (with --minify)
function foo(f){f.prop()}

// New output (with --minify)
function foo(o){let f=o.prop;f()}