Front end darsliklari moduli html, css, javascript
Write a function that inserts a white space between every instance of a lower character followed immediately by an upper character. Examples
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FRONT END full notes (7) (2022 05 08 17 42 47 UTC)
- Bu sahifa navigatsiya:
- 8. JAVASCRIPT – Arraylar va Looplar
- 9. JAVASCRIPT – Objects and Classes
- Object.freeze()
- Object.seal()
4.
Write a function that inserts a white space between every instance of a lower character followed immediately by an upper character. Examples insertWhitespace("SheWalksToTheBeach") ➞ "She Walks To The Beach" insertWhitespace("MarvinTalksTooMuch") ➞ "Marvin Talks Too Much" insertWhitespace("TheGreatestUpsetInHistory") ➞ "The Greatest Upset In History" 8. JAVASCRIPT – Arraylar va Looplar • Array nima? • Array Methodlari: index, length, json.stringify(), slice, splice, join(), concat(), push(), pop(), shift(), unshift() • Map, reduce, sort, filter, forEach • new Array('Apple', 'Banana’)// […], new Array(2) // length, forEach() const numbers = [65, 44, 12, 4]; numbers.forEach(myFunction) function myFunction(item, index, arr) { arr[index] = item * 10; } reduce() const array1 = [1, 2, 3, 4]; const reducer = (previousValue, currentValue) => previousValue + currentValue; // 1 + 2 + 3 + 4 console.log(array1.reduce(reducer)); // expected output: 10 // 5 + 1 + 2 + 3 + 4 console.log(array1.reduce(reducer, 5)); // expected output: 15 reduce(function callbackFn(previousValue, currentValue, currentIndex, array) { ... }, initialValue) var items = [ [1, 2], [3, 4], [5, 6] ]; • destructure var yourArr = [1, 2, 3] [one, , three] = yourArray 9. JAVASCRIPT – Objects and Classes • Object nima? access obj value with dot and [] const person = { fname:" John", lname:" Doe", age: 25 }; for (let x in person) { txt += person[x]; } person.nationality = "English"; delete person.age; or delete person["age"]; const myObj = { name: "John", age: 30, cars: [ {name:"Ford", "models":["Fiesta", "Focus", "Mustang"]}, {name:"BMW", "models":["320", "X3", "X5"]}, {name:"Fiat", "models":["500", "Panda"]} ] } acces nested objs Obj add, delete, update Object.keys(), Object.values(), Object.entries() [ [‘key’, ‘value’] ] const object1 = { a: 'somestring', b: 42, c: false }; console.log(Object.keys(object1)); // expected output: Array ["a", "b", "c"] const object1 = { a: 'somestring', b: 42 }; for (const [key, value] of Object.entries(object1)) { console.log(`${key}: ${value}`); } // expected output: // "a: somestring" // "b: 42" obj.freeze, obj.seal The Object.freeze() method freezes an object. A frozen object can no longer be changed; freezing an object prevents new properties from being added to it, const obj = { prop: 42 }; Object.freeze(obj); obj.prop = 33; // Throws an error in strict mode console.log(obj.prop); // expected output: 42 The Object.seal() method seals an object, preventing new properties from being added to it and marking all existing properties as non-configurable. Values of present properties can still be changed as long as they are writable. const object1 = { property1: 42 }; Object.seal(object1); object1.property1 = 33; console.log(object1.property1); // expected output: 33 delete object1.property1; // cannot delete when sealed console.log(object1.property1); // expected output: 33 • Functions in obj const person = { firstName: "John", lastName: "Doe", id: 5566, fullName: function() { return this.firstName + " " + this.lastName; } }; arrow functions and functions in obj • Classes —> destructure class Car { constructor(name, year) { this.name = name; this.year = year; } } let myCar = new Car("Ford", 2014); class ClassName { constructor() { ... } method_1() { ... } method_2() { ... } method_3() { ... } } class Car { constructor(name, year) { this.name = name; this.year = year; } age() { let date = new Date(); return date.getFullYear() - this.year; } } class Car { constructor(brand) { this.carname = brand; } present() { return 'I have a ' + this.carname; } } class Model extends Car { constructor(brand, mod) { super(brand); this.model = mod; } show() { return this.present() + ', it is a ' + this.model; } } let myCar = new Model("Ford", "Mustang"); • this keyword const person = { firstName: "John", lastName : "Doe", id : 5566, fullName : function() { return this.firstName + " " + this.lastName; } }; Download 105.45 Kb. Do'stlaringiz bilan baham: |
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