文本正则替换 模式

repl.js

// 此处所列函数只是框架，实际使用仍需要调整和修正
// 提供的是一个思路

// 替换函数是同步的
function replSync(txt) {
  let pick = (s, e) => txt.substring(s, e);

  const re = /\w/g;
  const buf = [];
  let lastIdx = 0;
  let m;
  while ((m = re.exec(txt)) !== null) {
    const {[0]: m0, index: idx} = m;
    if (idx !== lastIdx) {
      buf.push(pick(lastIdx, idx));
    }

    buf.push('new txt');

    lastIdx = idx + m0.length;
  }
  if (lastIdx < txt.length) {
    buf.push(pick(lastIdx, txt.length));
  }

  return buf.join('');
}

// 替换函数是异步的
async function replAsync(txt, processMatch) {
  let matches = [];
  const fill = (m, pre, con, suf, offset) => {
    matches.push({
      range: [offset + pre.length, offset + m.length - suf.length],
      m,
      pre, suf,
    });
  };

  let re = /\b(['"])(.+?)(\2)/g;
  txt.replace(re, fill);

  if (!matches.length) {
    return txt;
  }

  const errors = [];
  await Promise.all(matches.map((m) => {
    return new Promise((resolve, reject) => {
      processMatch(m, (err, ret) => {
        if (err) {
          errors.push({m, err});
        } else {
          m.ret = ret;
        }

        resolve();
      });
    });
  }));

  if (errors.length) {
    let err = new Error();
    err.errors = errors;
    throw err;
  }

  let buf = [];
  matches.forEach((m, idx) => {
    buf.push(
      s.substring(
        idx === 0 ? 0 : matches[idx - 1].range[1],
        m.range[0]
      )
    );

    buf.push(m.ret);
  });

  buf.push(
    s.substring(
      matches[matches.length - 1].range[1],
      s.length
    )
  );

  return buf.join('');
}