如何使用javascript中先前函数的输出调用函数

Question

停留在 JavaScript 中的这个小部分。我目前有一个程序，当按下按钮时，它会获取一个输入文件并逐行读取并确定哪些行是回文，然后将它们输出到控制台。我的目标是获取这些回文并在它们上运行下一个函数（称为频率）并将函数的结果输出到控制台。但是，我不知道该怎么做。

这是我的代码：

window.addEventListener('load', function() {
  document.getElementById("myBtn").addEventListener("click", function() {
    var reader = new FileReader();
    reader.addEventListener('load', function() {
      const sentences = this.result.split(/\r?\n/);
      const palindromes = sentences.filter((line) => {
        return palindrome(line);
      });
      console.log('all sentences:', sentences);
      console.log('only palindromes:', palindromes);
    });
    reader.readAsText(document.querySelector('input').files[0]);
  });
}, true);

function palindrome(str) {
  if (str === '')
    return false;
  var re = /[\W_]/g;
  var lowRegStr = str.toLowerCase().replace(re, '');
  var reverseStr = lowRegStr.split('').reverse().join('');
  return reverseStr === lowRegStr;
}

function frequency(str) {
//some code
}

<label for="upload">Upload file to find palindromes:</label>
<br />
<input type="file" name="upload" id="upload">
<button id="myBtn">Go!</button>

有什么建议吗？谢谢！

编辑：这是我输入的内容

 mom
 Racecar!
 another line

Answer 1

你需要在回文上运行它

const re = /[\W_]/g;
const clean = word => word.replace(re, '');
const palindrome = str => {
  if (str === '') return false;
  var lowRegStr = clean(str).toLowerCase(); // compare clean
  var reverseStr = lowRegStr.split('').reverse().join('');
  console.log(lowRegStr,reverseStr)
  return reverseStr === lowRegStr;
};

const frequency = s => [...s].reduce((a, c) => (a[c] = a[c] + 1 || 1) && a, {}); // https://stackoverflow.com/a/58600923/295783

const process = file => {
  const sentences = file.split(/\r?\n/);
  const palindromes = sentences.map(word => clean(word).toLowerCase()).filter(palindrome); // filter after clean
  const freq = palindromes.map(palindrome => ({
    palindrome,
    freq: frequency(palindrome)
  }));

  const freqAll = frequency(palindromes.join(""))

  console.log('all sentences:', sentences);
  console.log('only palindromes:', palindromes);
  console.log(freq);
  console.log("All",freqAll);
}

// replace the test result below with your file getting
const result = `mom
Racecar!
another line`
process(result); // goes into the success of the file getting

替换以const result 开头的行，直到结尾为

window.addEventListener('load', function() {
  document.getElementById("myBtn").addEventListener("click", function() {
    const reader = new FileReader();
    reader.addEventListener('load', function() { process(this.result) });
    reader.readAsText(document.querySelector('input').files[0]);
  });
});