如何通过键从chrome.storage.local获取值？键值访问语法问题求助

Hey there! The issue you're hitting is a common one with JavaScript object property access — let's break it down and fix your code.

The Core Problem #

In JavaScript, when you use the dot notation (like items.tile), you're referencing a property name as a literal string. But when you want to use a variable (like str or Keys[i]) to access a property, you need to use bracket notation instead.

Let's Fix Your Code Snippets #

Let's go through each problematic line one by one:

1. Replacing items.str with items[str]
   Your str variable holds the string "tile", so instead of trying to access a property named str (which doesn't exist), use brackets to pass the variable's actual value:

   console.log(items[str]); // This will correctly log the value of items.tile
   

2. Fixing the while loop with items[Keys[i]]
   Similarly, Keys[i] is a variable that holds your target property name, so bracket notation is required here too. I also fixed a small typo (your array was named value but you were pushing to values):

   var values = []; // Fixed variable name to match the push target
   chrome.storage.local.get(null, function(items) {
     var Keys = Object.keys(items);
     console.log(Keys);
     let i = Keys.length; // Use let for proper block scoping instead of global i
     console.log(items.tile); // Works because "tile" is a literal property name
     var str = String(Keys[6]);
     console.log(str); // Outputs "tile"
     console.log(items[str]); // Now works correctly!
     
     while (i--) {
       values.push(items[Keys[i]]); // Bracket notation for dynamic variable keys
       console.log(values);
     }
   })
   

Why This Works #

• Dot notation (obj.property) only works when you know the exact property name ahead of time (it has to be a valid identifier with no spaces or special characters).
• Bracket notation (obj[variable]) lets you compute the property name dynamically using variables, strings, or even expressions — perfect for cases like looping through object keys.

That should get your code working as expected!

内容的提问来源于stack exchange，提问作者Weee