TheObject.keys()method# TheObject.keys()method returns an array of keys from an object. You pass in the object as an argument. // logs ["sandwich", "chips", "drink"]letkeys=Object.keys(lunch);console.log(keys); You can combine it with afor...ofloop (or any of the other array...
-1:100*e}（2）连等连等是利用赋值运算表达式会返回所赋的值，并且执行顺序是从右到左的，如下：o...
Core Method Object.keys() with iteration reduce() with functional style Readability More explicit, easier to follow More concise but less beginner-friendly Flexibility Allows additional operations within the loop Ideal for direct transformationsAlshifa...
Looping over a String Example letlanguage ="JavaScript"; lettext =""; for(letx of language) { text += x +" "; } Try it Yourself » Learn more in the chapter:JavaScript Loop For/In/Of. JavaScript Maps Being able to use an Object as a key is an important Map feature. ...
EnhancedForLoop: a “for-in” or “for-of” loop; use EnhancedForLoop.getIterator() to access the loop iterator (which may be a expression or variable declaration), and EnhancedForLoop.getIterationDomain() to access the expression being iterated over. ForInStmt, ForOfStmt: a “for-in”...
destination.on("error", err => process.exit()); // Use a for/await loop to asynchronously read chunks from the input stream for await (let chunk of source) { // Write the chunk and wait until there is more room in the buffer. await write(destination, chunk); } } // Copy ...
Iteration order of keys over an object which contains spread syntax in later versions of Chrome and Node.js may be altered. When toplevel is enabled, UglifyJS effectively assumes input code is wrapped within function(){ ... }, thus forbids aliasing of declared global variables: A = "FAIL...
JS-son supports an alternative goal-based reasoning loop. Here, we show a minimal working example of an agent that employs this approach. Our agent has merely one goal:const goals = { praiseDog: Goal('praiseDog', false, { dogName: 'Hasso' }) }...
Possible Values:"average" |"color-burn" |"color-dodge" |"color" |"darken" |"destination-atop" |"destination-in" |"destination-out" |"destination-over" |"difference" |"exclusion" |"hard-light" |"hue" |"invert" |"lighten" |"lighter" |"luminosity" |"minus" |"multiply" |"normal" |...
Currently, because the experience property is not enumerable, the use of the for...in loop can’t enumerate through the properties, and the result is: Techbook has prototype The new experience property’s enumerable attribute is then changed to true, because the property descriptor for experience...