部分Lodash函数出现‘not a function’错误，求解决方案

It sounds like your issue boils down to version differences between Lodash 3.x and 4.x, plus a few common pitfalls. Let's break this down clearly:

1. Why Some Functions Work and Others Don't #

• Lodash 3.x Limitations: Functions like _.minBy and _.maxBy didn't exist in Lodash 3.x—they were introduced in Lodash 4.0.0. That's exactly why you're getting "not a function" errors for those when using 3.1.0.
  • _.cloneDeep does exist in 3.x (added in 3.0.0), so if that's throwing an error, double-check for typos (it's strict camelCase: cloneDeep, not lowercase or mixed case) or verify the CDN script loaded properly (check your browser's network tab for failed requests).
• Lodash 4.x: If you tried 4.x and still had issues, make sure you're loading a full build of Lodash (not a modular subset) and that no other libraries are overwriting the _ variable.

2. Practical Solutions #

Option 1: Upgrade to Lodash 4.x (Recommended) #

Switch to a recent 4.x version (like 4.17.21, the latest stable) to unlock all the functions you need. Here's how to update your code:

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.21/lodash.min.js"></script>
<script type="text/javascript">
  var drinks = [
    { 'name': 'Coke', 'quantity': 2 },
    { 'name': 'Red Bull', 'quantity': 6 }
  ];
  
  // Your existing working code
  var currentDrinks = _.map(drinks, 'name');
  console.log(currentDrinks); // ['Coke', 'Red Bull']
  
  // Test _.minBy
  var leastQuantityDrink = _.minBy(drinks, 'quantity');
  console.log(leastQuantityDrink); // { name: 'Coke', quantity: 2 }
  
  // Test _.cloneDeep
  var deepCopy = _.cloneDeep(drinks);
  deepCopy[0].quantity = 10; // Won't affect the original array
  console.log(drinks[0].quantity); // Still 2
</script>

Option 2: Stay on Lodash 3.x (If Necessary) #

If you can't upgrade, replicate the missing functions using 3.x's existing tools:

• For _.minBy/_.maxBy: Use _.reduce to find the object with the min/max property value:

  // Find drink with minimum quantity
  var minDrink = _.reduce(drinks, function(prev, curr) {
    return prev.quantity < curr.quantity ? prev : curr;
  });
  
  // Find drink with maximum quantity
  var maxDrink = _.reduce(drinks, function(prev, curr) {
    return prev.quantity > curr.quantity ? prev : curr;
  });
  

• For _.cloneDeep: Double-check the camelCase syntax and ensure you're loading the full Lodash build (not a stripped-down version).

3. Common Pitfalls to Rule Out #

• Duplicate Lodash Loads: If you're loading multiple versions of Lodash (e.g., 3.x and 4.x), this can overwrite functions and cause conflicts. Scan your HTML for duplicate script tags.
• Library Conflicts: Other libraries like Underscore.js also use the _ variable. If you're using both, use Lodash's noConflict mode to avoid clashes:

  var lodash = _.noConflict();
  // Use lodash.minBy instead of _.minBy
  var minDrink = lodash.minBy(drinks, 'quantity');
  

内容的提问来源于stack exchange，提问作者User213