Function handler

packages/vite/rolldown.config.ts:230–275

(code, id)

        id: new RegExp(`(?:${Object.keys(deps).join('|')})$`),
      },
      handler(code, id) {
        const file = Object.keys(deps).find((file) =>
          id.replace(/\\/g, '/').endsWith(file),
        )
        if (!file) return

        for (const { src, replacement, pattern } of deps[file]) {
          const magicString = new MagicString(code)

          if (src) {
            const pos = code.indexOf(src)
            if (pos < 0) {
              this.error(
                `Could not find expected src "${src}" in file "${file}"`,
              )
            }
            transformed[file] = true
            magicString.overwrite(pos, pos + src.length, replacement)
          }

          if (pattern) {
            let match
            while ((match = pattern.exec(code))) {
              transformed[file] = true
              const start = match.index
              const end = start + match[0].length
              let _replacement = replacement
              for (let i = 1; i <= match.length; i++) {
                _replacement = _replacement.replace(`$${i}`, match[i] || '')
              }
              magicString.overwrite(start, end, _replacement)
            }
            if (!transformed[file]) {
              this.error(
                `Could not find expected pattern "${pattern}" in file "${file}"`,
              )
            }
          }

          code = magicString.toString()
        }

        console.log(`shimmed: ${file}`)

        return code
      },
    },
    buildEnd(err) {
      if (this.meta.watchMode) return