How to build metafile(manifest.json)?

[Paosder]

Hello, is there any option to build metafile (ex. manifest.json)?

I found that esbuild supports the option 'metafile', however snowpack seems doesn't.

('metafile' option is not documented, but it exists.)
evanw/esbuild#331

Or is there any way to generate metafile ?

[FredKSchott]

We've talked about adding a manifest file to our Webpack bundling plugin output, so that you could easily get it that way. This reminds me to spin up a prioritized issue for that.

If you want this for the unbundled build, it would be great to better understand what data you're looking for, and what you're trying to do with it.

[FredKSchott]

Do you have an example of what esbuild's metafile looks like that you could share? I'm not sure how this would work, since our build is unbundled we'd need to add many entries over many different calls to build()

[Paosder]

Sorry for the late response. I checked result of esbuild's manifest file, however it isn't what I wanted. I think I misunderstood about esbuild's metafile option.

// result of esbuild's metafile
{
  "inputs": {
    "node_modules/mathlive/dist/mathlive.mjs": {
      "bytes": 1213056,
      "imports": []
    },
    "src/editor.tsx": {
      "bytes": 1086,
      "imports": [
        {
          "path": "node_modules/mathlive/dist/mathlive.mjs"
        }
      ]
    }
  },
  "outputs": {
    "dist/editor.js.map": {
      "imports": [],
      "inputs": {},
      "bytes": 1692906
    },
    "dist/editor.js": {
      "imports": [],
      "inputs": {
        "node_modules/mathlive/dist/mathlive.mjs": {
          "bytesInOutput": 526300
        },
        "src/editor.tsx": {
          "bytesInOutput": 488
        }
      },
      "bytes": 527214
    }
  }
}

What I want to do is just get manifest.json that list of hashed filename(like example below), in unbundled build.

{
  "main.js": "en34jdfmasdke45.js",
  "editor.js": "5df4wr43k3mwfj.js"
}

I investigated many ways to solve this issue, but I couldn't get clear solution(or I just missed something). I know this feature can easily get under bundled build via webpack(actually, webpack plugin). This feature may not attracted to most people, and it's hard to implement, however it would be appreciated if this feature landed on unbundled build.

[FredKSchott]

Today we don't do filename hashing in the unbundled build, every source file maps to the same filename in the build destination (although file extension may change, like .jsx -> .js).

[Paosder]

I'm confused because of the cache burst method used by the bundle build, then only server can control to serve updated file(like given dummy params to not use previous cache data, not just hashing filename) when using unbundled build?

[FredKSchott]

I can clarify:

• Our bundled build plugin for webpack does use filename hashing. Webpack plugin should output asset-manifest.json #955 tracks adding a manifest file to it.
• Our unbundled build does not do filename hashing. No manifest file needed.