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export wasm files to better support bundling use cases#4208

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amaanq merged 1 commit intotree-sitter:masterfrom
vemoo:export-wasm
Apr 19, 2025
Merged

export wasm files to better support bundling use cases#4208
amaanq merged 1 commit intotree-sitter:masterfrom
vemoo:export-wasm

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@vemoo
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@vemoo vemoo commented Feb 16, 2025

When using a bundler, calling Parser.init() without options may not work because the file won't be where it expects it.

With esbuild for example a better way is to import the wasm file with the file loader and provide it on Parser.init:

  • index.js
import path from "node:path";
import { Parser } from "web-tree-sitter";
import TreeSitterWasmUrl from "web-tree-sitter/tree-sitter.wasm";

await Parser.init({
    locateFile: (url, scriptDir) => {
        if (url === "tree-sitter.wasm") {
            return path.join(scriptDir, TreeSitterWasmUrl);
        }
    },
});
  • build.js
import esbuild from "esbuild";

await esbuild.build({
    entryPoints: ["index.js"],
    outdir: "dist",
    bundle: true,
    platform: "node",
    format: "esm",
    loader: {
        ".wasm": "file",
    },
});

This will copy the wasm file to the output directory and replace TreeSitterWasmUrl with the relative path to it.

Unfortunately at the moment it fails with:

✘ [ERROR] Could not resolve "web-tree-sitter/tree-sitter.wasm"

    index.js:3:30:
      3 │ import TreeSitterWasmUrl from "web-tree-sitter/tree-sitter.wasm";
        ╵                               ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

  The path "./tree-sitter.wasm" is not exported by package "web-tree-sitter":

    node_modules/web-tree-sitter/package.json:19:13:
      19 │   "exports": {
         ╵              ^

  You can mark the path "web-tree-sitter/tree-sitter.wasm" as external to exclude it from the
  bundle, which will remove this error and leave the unresolved path in the bundle.

This PR fixes it.

@amaanq
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amaanq commented Apr 19, 2025

awesome, thank you for the detailed explanation!

@amaanq amaanq merged commit 4dffb81 into tree-sitter:master Apr 19, 2025
@WillLillis WillLillis added the ci:backport release-0.25 Backport label label Apr 19, 2025
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tree-sitter-ci-bot bot commented Apr 19, 2025

Successfully created backport PR for release-0.25:

@tree-sitter-ci-bot tree-sitter-ci-bot bot mentioned this pull request Apr 19, 2025
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@mitya57 mitya57 mentioned this pull request Jul 9, 2025
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@vemoo @amaanq @WillLillis