esbuild 0.27.2

v0.27.2

on Node.js NPM

Allow import path specifiers starting with #/ (#4361)

Previously the specification for package.json disallowed import path specifiers starting with #/, but this restriction has recently been relaxed and support for it is being added across the JavaScript ecosystem. One use case is using it for a wildcard pattern such as mapping #/* to ./src/* (previously you had to use another character such as #_* instead, which was more confusing). There is some more context in nodejs/node#49182.

This change was contributed by @hybrist.

Automatically add the -webkit-mask prefix (#4357, #4358)

This release automatically adds the -webkit- vendor prefix for the mask CSS shorthand property:

/* Original code */
main {
  mask: url(x.png) center/5rem no-repeat
}

/* Old output (with --target=chrome110) */
main {
  mask: url(x.png) center/5rem no-repeat;
}

/* New output (with --target=chrome110) */
main {
  -webkit-mask: url(x.png) center/5rem no-repeat;
  mask: url(x.png) center/5rem no-repeat;
}

This change was contributed by @BPJEnnova.

Additional minification of switch statements (#4176, #4359)

This release contains additional minification patterns for reducing switch statements. Here is an example:

// Original code
switch (x) {
  case 0:
    foo()
    break
  case 1:
  default:
    bar()
}

// Old output (with --minify)
switch(x){case 0:foo();break;case 1:default:bar()}

// New output (with --minify)
x===0?foo():bar();

Forbid using declarations inside switch clauses (#4323)

This is a rare change to remove something that was previously possible. The Explicit Resource Management proposal introduced using declarations. These were previously allowed inside case and default clauses in switch statements. This had well-defined semantics and was already widely implemented (by V8, SpiderMonkey, TypeScript, esbuild, and others). However, it was considered to be too confusing because of how scope works in switch statements, so it has been removed from the specification. This edge case will now be a syntax error. See tc39/proposal-explicit-resource-management#215 and rbuckton/ecma262#14 for details.

Here is an example of code that is no longer allowed:

switch (mode) {
  case 'read':
    using readLock = db.read()
    return readAll(readLock)

  case 'write':
    using writeLock = db.write()
    return writeAll(writeLock)
}

That code will now have to be modified to look like this instead (note the additional { and } block statements around each case body):

switch (mode) {
  case 'read': {
    using readLock = db.read()
    return readAll(readLock)
  }
  case 'write': {
    using writeLock = db.write()
    return writeAll(writeLock)
  }
}

This is not being released in one of esbuild's breaking change releases since this feature hasn't been finalized yet, and esbuild always tracks the current state of the specification (so esbuild's previous behavior was arguably incorrect).