protoc-gen-es

@bufbuild/protoc-gen-es

The code generator plugin for Protocol Buffers for ECMAScript. Learn more about the project at github.com/bufbuild/protobuf-es.

Installation

protoc-gen-es generates base types - messages and enumerations - from your Protocol Buffer schema. The generated code requires the runtime library @bufbuild/protobuf. It is compatible with Protocol Buffer compilers like buf and protoc.

To install the plugin and the runtime library, run:

npm install --save-dev @bufbuild/protoc-gen-es
npm install @bufbuild/protobuf

We use peer dependencies to ensure that code generator and runtime library are compatible with each other. Note that npm installs them automatically, but yarn and pnpm do not.

Generating code

With buf

npm install --save-dev @bufbuild/buf

Add a new configuration file buf.gen.yaml:

# buf.gen.yaml defines a local generation template.
# For details, see https://docs.buf.build/configuration/v1/buf-gen-yaml
version: v1
plugins:
  # This will invoke protoc-gen-es and write output to src/gen
  - plugin: es
    out: src/gen
    opt: 
      # Add more plugin options here
      - target=ts

To generate code for all protobuf files within your project, simply run:

npx buf generate

Note that buf can generate from various inputs, not just local protobuf files.

With protoc

PATH=$PATH:$(pwd)/node_modules/.bin \
  protoc -I . \
  --es_out src/gen \
  --es_opt target=ts \
  a.proto b.proto c.proto

Note that we are adding node_modules/.bin to the $PATH, so that the protocol buffer compiler can find them. This happens automatically with npm scripts.

Since yarn v2 and above does not use a node_modules directory, you need to change the variable a bit:

PATH=$(dirname $(yarn bin protoc-gen-es)):$PATH

Plugin options

target

This option controls whether the plugin generates JavaScript, TypeScript, or TypeScript declaration files.

Possible values:

• target=js - generates a _pb.js file for every .proto input file.
• target=ts - generates a _pb.ts file for every .proto input file.
• target=dts - generates a _pb.d.ts file for every .proto input file.

Multiple values can be given by separating them with +, for example target=js+dts.

By default, we generate JavaScript and TypeScript declaration files, which produces the smallest code size and is the most compatible with various bundler configurations. If you prefer to generate TypeScript, use target=ts.

import_extension=.js

By default, protoc-gen-es (and all other plugins based on @bufbuild/protoplugin) uses a .js file extensions in import paths, even in TypeScript files.

This is unintuitive, but necessary for ECMAScript modules in Node.js. Unfortunately, not all bundlers and tools have caught up yet, and Deno requires .ts. With this plugin option, you can replace .js extensions in import paths with the given value. For example, set

• import_extension=none to remove the .js extension.
• import_extension=.ts to replace the .js extension with .ts.

js_import_style

By default, protoc-gen-es (and all other plugins based on @bufbuild/protoplugin) generate ECMAScript import and export statements. For use cases where CommonJS is difficult to avoid, this option can be used to generate CommonJS require() calls.

Possible values:

• js_import_style=module generate ECMAScript import / export statements - the default behavior.
• js_import_style=legacy_commonjs generate CommonJS require() calls.

keep_empty_files=true

By default, protoc-gen-es (and all other plugins based on @bufbuild/protoplugin) omit empty files from the plugin output. This option disables pruning of empty files, to allow for smooth interoperation with Bazel and similar tooling that requires all output files to be declared ahead of time. Unless you use Bazel, it is very unlikely that you need this option.

ts_nocheck=false

By default, protoc-gen-es (and all other plugins based on @bufbuild/protoplugin) generate an annotation at the top of each file: // @ts-nocheck.

We generate the annotation to support a wide range of compiler configurations and future changes to the language. But there can be situations where the annotation shadows an underlying problem, for example an unresolvable import. To remove the annotation and to enable type checks, set the plugin option ts_nocheck=false.