api

Overview ¶

This API exposes esbuild's two main operations: building and transforming. It's intended for integrating esbuild into other tools as a library.

If you are just trying to run esbuild from Go without the overhead of creating a child process, there is also an API for the command-line interface itself: https://godoc.org/github.com/evanw/esbuild/pkg/cli.

Build API ¶

This function runs an end-to-end build operation. It takes an array of file paths as entry points, parses them and all of their dependencies, and returns the output files to write to the file system. The available options roughly correspond to esbuild's command-line flags.

Example usage:

package main

import (
    "fmt"
    "io/ioutil"

    "github.com/evanw/esbuild/pkg/api"
)

func main() {
    result := api.Build(api.BuildOptions{
        EntryPoints: []string{"input.js"},
        Outfile:     "output.js",
        Bundle:      true,
    })

    fmt.Printf("%d errors and %d warnings\n",
        len(result.Errors), len(result.Warnings))

    for _, out := range result.OutputFiles {
        ioutil.WriteFile(out.Path, out.Contents, 0644)
    }
}

Transform API ¶

This function transforms a string of source code into JavaScript. It can be used to minify JavaScript, convert TypeScript/JSX to JavaScript, or convert newer JavaScript to older JavaScript. The available options roughly correspond to esbuild's command-line flags.

Example usage:

package main

import (
    "fmt"
    "os"

    "github.com/evanw/esbuild/pkg/api"
)

func main() {
    jsx := `
        import * as React from 'react'
        import * as ReactDOM from 'react-dom'

        ReactDOM.render(
            <h1>Hello, world!</h1>,
            document.getElementById('root')
        );
    `

    result := api.Transform(jsx, api.TransformOptions{
        Loader: api.LoaderJSX,
    })

    fmt.Printf("%d errors and %d warnings\n",
        len(result.Errors), len(result.Warnings))

    os.Stdout.Write(result.JS)
}