Search addon is off on lines containing emojis

[Tyriar]

VS Code issue: microsoft/vscode#37440

[marg51]

The error most likely comes from https://github.com/xtermjs/xterm.js/blob/master/src/addons/search/SearchHelper.ts#L117

I suppose a quick fix could look like:

private _findInLine(term: string, line: number): ISearchResult {
  const lowerStringLine = this._terminal.buffer.translateBufferLineToString(line, true).toLowerCase()
  const lowerTerm = term.toLowerCase()
  const searchIndex = lowerStringLine.indexOf(lowerTerm)

  if (searchIndex >= 0) {
    // ⬇️

    for (let i = 0; i < searchIndex; i++) {
      const current_char_width = this._terminal.buffer.lines[line][i][CHAR_DATA_WIDTH_INDEX]

      if (this._terminal.buffer.lines[line][CHAR_DATA_WIDTH_INDEX] === 0) 
          searchIndex--
      else if (this._terminal.buffer.lines[line][CHAR_DATA_WIDTH_INDEX] === 2) 
          searchIndex-- 
    }

    // ⬆️
    return {
      term,
      col: searchIndex,
      row: line,
    }
  }
}

I wish I could do more, but this addon has no tests.

[Tyriar]

Thanks @marg51, you were on the right track. I put a PR out to fix this #1211