如何检测数组中是否包含子数组？JavaScript实现方案咨询

Oh right, this is a classic JavaScript gotcha! When you use indexOf to look for an array inside another array, it checks for exact memory references—not matching content. That’s why ['>', 'PSF', 10] !== ['>', 'PSF', 10] under the hood, even though they look identical. Let’s walk through a few reliable ways to solve this:

1. Use findIndex with a Custom Equality Check #

This is the most robust approach, especially if you might have nested arrays or need precise control over what counts as "equal." First, make a helper function to compare two arrays:

function arraysAreEqual(arrA, arrB) {
  // If lengths don't match, they can't be equal
  if (arrA.length !== arrB.length) return false;

  // Loop through each element to compare
  for (let i = 0; i < arrA.length; i++) {
    // Recursively check nested arrays
    if (Array.isArray(arrA[i]) && Array.isArray(arrB[i])) {
      if (!arraysAreEqual(arrA[i], arrB[i])) return false;
    } 
    // Strict equality check for primitive values
    else if (arrA[i] !== arrB[i]) {
      return false;
    }
  }
  return true;
}

Then use it with findIndex to get the index of your target subarray:

let arr = ["all", ['>', 'PSF', 10]];
let segment = ['>', 'PSF', 10];

const targetIndex = arr.findIndex(item => arraysAreEqual(item, segment));
// targetIndex will be 1, just like you expected!

2. Quick-and-Dirty String Conversion (For Simple Cases) #

If your arrays only contain primitive values (strings, numbers, booleans) and no characters that would break string serialization (like commas or quotes), you can use JSON.stringify to compare array content:

let arr = ["all", ['>', 'PSF', 10]];
let segment = ['>', 'PSF', 10];

const targetIndex = arr.findIndex(item => JSON.stringify(item) === JSON.stringify(segment));
// Also returns 1 here

Heads up though: This has limitations! For example, JSON.stringify(["a,b", "c"]) matches JSON.stringify(["a", "b,c"]), even though the arrays are different. It also fails with non-serializable values like functions, undefined, or Symbols. Use this only when you’re sure your array contents play nice with JSON.

3. Check for Existence (Not Index) with some #

If you don’t need the exact index and just want to know if the subarray exists, some is a cleaner option with the same helper function:

const segmentExists = arr.some(item => arraysAreEqual(item, segment));
// segmentExists will be true

Pick the method that fits your use case—for most scenarios, the custom equality check with findIndex is the safest bet.

内容的提问来源于stack exchange，提问作者yoursweater