Function handler

packages/vite/src/node/plugins/assetImportMetaUrl.ts:64–177

(code, id)

        code: assetImportMetaUrlRE,
      },
      async handler(code, id) {
        let s: MagicString | undefined
        const re = new RegExp(assetImportMetaUrlRE)
        const cleanString = stripLiteral(code)

        let match: RegExpExecArray | null
        while ((match = re.exec(cleanString))) {
          const [[startIndex, endIndex], [urlStart, urlEnd]] =
            match.indices as Array<[number, number]>
          if (hasViteIgnoreRE.test(code.slice(startIndex, urlStart))) continue

          const rawUrl = code.slice(urlStart, urlEnd)

          if (!s) s = new MagicString(code)

          // potential dynamic template string
          if (rawUrl[0] === '`' && rawUrl.includes('${')) {
            const queryDelimiterIndex = getQueryDelimiterIndex(rawUrl)
            const hasQueryDelimiter = queryDelimiterIndex !== -1
            const pureUrl = hasQueryDelimiter
              ? rawUrl.slice(0, queryDelimiterIndex) + '`'
              : rawUrl
            const queryString = hasQueryDelimiter
              ? rawUrl.slice(queryDelimiterIndex, -1)
              : ''
            const ast = this.parse(pureUrl)
            const templateLiteral = (ast as any).body[0].expression
            if (templateLiteral.expressions.length) {
              const pattern = buildGlobPattern(templateLiteral)
              if (pattern[0] === '*') {
                // don't transform for patterns like this
                // because users won't intend to do that in most cases
                continue
              }

              const globOptions = {
                eager: true,
                import: 'default',
                // A hack to allow 'as' & 'query' exist at the same time
                query: injectQuery(queryString, 'url'),
              }
              s.update(
                startIndex,
                endIndex,
                `new URL((import.meta.glob(${JSON.stringify(
                  pattern,
                )}, ${JSON.stringify(
                  globOptions,
                )}))[${pureUrl}], import.meta.url)`,
              )
              continue
            }
          }

          const url = rawUrl.slice(1, -1)
          if (isDataUrl(url)) {
            continue
          }