evanw/esbuild v0.19.11

on GitHub

Fix TypeScript-specific class transform edge case (#3559)

The previous release introduced an optimization that avoided transforming super() in the class constructor for TypeScript code compiled with useDefineForClassFields set to false if all class instance fields have no initializers. The rationale was that in this case, all class instance fields are omitted in the output so no changes to the constructor are needed. However, if all of this is the case and there are #private instance fields with initializers, those private instance field initializers were still being moved into the constructor. This was problematic because they were being inserted before the call to super() (since super() is now no longer transformed in that case). This release introduces an additional optimization that avoids moving the private instance field initializers into the constructor in this edge case, which generates smaller code, matches the TypeScript compiler's output more closely, and avoids this bug:

// Original code
class Foo extends Bar {
  #private = 1;
  public: any;
  constructor() {
    super();
  }
}

// Old output (with esbuild v0.19.9)
class Foo extends Bar {
  constructor() {
    super();
    this.#private = 1;
  }
  #private;
}

// Old output (with esbuild v0.19.10)
class Foo extends Bar {
  constructor() {
    this.#private = 1;
    super();
  }
  #private;
}

// New output
class Foo extends Bar {
  #private = 1;
  constructor() {
    super();
  }
}

Minifier: allow reording a primitive past a side-effect (#3568)

The minifier previously allowed reordering a side-effect past a primitive, but didn't handle the case of reordering a primitive past a side-effect. This additional case is now handled:

// Original code
function f() {
  let x = false;
  let y = x;
  const boolean = y;
  let frag = $.template(`<p contenteditable="${boolean}">hello world</p>`);
  return frag;
}

// Old output (with --minify)
function f(){const e=!1;return $.template(`<p contenteditable="${e}">hello world</p>`)}

// New output (with --minify)
function f(){return $.template('<p contenteditable="false">hello world</p>')}

Minifier: consider properties named using known Symbol instances to be side-effect free (#3561)

Many things in JavaScript can have side effects including property accesses and ToString operations, so using a symbol such as Symbol.iterator as a computed property name is not obviously side-effect free. This release adds a special case for known Symbol instances so that they are considered side-effect free when used as property names. For example, this class declaration will now be considered side-effect free:

class Foo {
  *[Symbol.iterator]() {
  }
}

Provide the stop() API in node to exit esbuild's child process (#3558)

You can now call stop() in esbuild's node API to exit esbuild's child process to reclaim the resources used. It only makes sense to do this for a long-lived node process when you know you will no longer be making any more esbuild API calls. It is not necessary to call this to allow node to exit, and it's advantageous to not call this in between calls to esbuild's API as sharing a single long-lived esbuild child process is more efficient than re-creating a new esbuild child process for every API call. This API call used to exist but was removed in version 0.9.0. This release adds it back due to a user request.