Perfect. To make the chapter examples more realistic, we are going to build an array of objects, which looks like Listing 5-4.let apressBooks = [ { "id": 111, "title": "C# 6.0", "author": "ANDREW TROELSEN", "rating": [4.7], "reviews": [{good : 4 , excellent : 12}] },...
lastIndexOf finds the location of the last occurrence of that element.find. To check if a specific element is present in an array, use the Findindex function. Find returns the value of the element while findIndex
frenchRoast, decaf];varcoffeeSizes = [small, medium, large];// build new objects that are combinations of the above// and put them into a new arrayvarcoffees = coffeeTypes.reduce(function(previous, current) {varnewCoffee = coffeeSizes.map(function(mixin) {// `plusmix` function for funct...
The following code iterates an array (arr), and extracts and prints the index and elements.// creating an array const arr = ["New Delhi", "New York", "California", "London"]; // Iterating an array with index and element for (const [key, value] of arr.entries()) { console.log...
Array flatMap() Array filter() Array reduce() Array reduceRight() See Also: Basic Array Methods Array Search Methods Array Sort MethodsArray every() Array some() Array from() Array keys() Array entries() Array with() Array Spread (...) ...
首先是可迭代对象:这些是可以被迭代的类型,如 Array、Set 和 Map。其次,是执行迭代的迭代器对象本身。第三,是保存迭代每一步结果的迭代结果对象。 可迭代对象是任何具有特殊迭代器方法的对象,该方法返回一个迭代器对象。迭代器是任何具有返回迭代结果对象的next()方法的对象。而迭代结果对象是具有名为value和done的...
Other array methods join() converts holes, undefineds, and nulls to empty strings: > ['a',, 'b'].join('-') 'a--b' > [ 'a', undefined, 'b' ].join('-') 'a--b' sort() preserves holes while sorting: > ['a',, 'b'].sort() // length of result is 3 [ 'a', 'b...
The fetch function retrieves data as JSON array from the provided URL. With forEach, we go through the array. Object.entries(obj).forEach(([key, value]) => { console.log(`${key} ${value}`); }); We go over the entries of each object and print the key and the value to the ...
("utf-8"); // For converting bytes to textlet body = ""; // Text read so farwhile(true) { // Loop until we exit belowlet {done, value} = await reader.read(); // Read a chunkif (value) { // If we got a byte array:if (processChunk) { // Process the bytes iflet ...
(3); // assign row values by sparse array (where array element 0 is undefined) const values = [] values[5] = 7; values[10] = 'Hello, World!'; row.values = values; expect(row.getCell(1).value).toBeNull(); expect(row.getCell(5).value).toEqual(7); expect(row.getCell(10)....