javascript-objects

问题 I have an array of objects named data , like so: data = [{"timeslot":"7pm-8pm","Monday":60,"Tuesday":55}, {"timeslot":"8pm-9pm","Monday":70,"Tuesday":60}, {"timeslot":"9pm-10pm","Monday":40,"Tuesday":37}] I want to get from this array three new arrays, like so: timeslot = ["7pm-8pm", "8pm-9pm", "9pm-10pm"] monday = [60, 70, 40] tuesdat = [55, 60, 37] Effectively grouping the data values by the data property name to which they belong. Here is my Javascript var timeslot = []; var monday = [];

问题 const myObj = { a: [1, 2, 3], b: [2, 4, 6], c: [10, 20, 30] } Into const myCollection = [ {a: 1, b: 2, c: 10}, {a: 2, b: 4, c: 20}, {a: 3, b: 6, c: 30} ] I tried combinations of Object.entries , Object.keys and map but I'm always finding myself iterating twice or more over myObj and I'm not happy with any solution I came up with. So what is the most efficient (in terms of time complexity) and elegant way that you can think to achieve that? 回答1: You could reduce the entries and map nested

问题 const myObj = { a: [1, 2, 3], b: [2, 4, 6], c: [10, 20, 30] } Into const myCollection = [ {a: 1, b: 2, c: 10}, {a: 2, b: 4, c: 20}, {a: 3, b: 6, c: 30} ] I tried combinations of Object.entries , Object.keys and map but I'm always finding myself iterating twice or more over myObj and I'm not happy with any solution I came up with. So what is the most efficient (in terms of time complexity) and elegant way that you can think to achieve that? 回答1: You could reduce the entries and map nested

问题 How do I display the content of a JavaScript object in a string format like when we alert a variable? The same formatted way I want to display an object. 回答1: If you want to print the object for debugging purposes, use the code: var obj = {prop1: 'prop1Value', prop2: 'prop2Value', child: {childProp1: 'childProp1Value'}} console.log(obj) will display: Note: you must only log the object. For example, this won't work: console.log('My object : ' + obj) Note ' : You can also use a comma in the log

问题 How do I display the content of a JavaScript object in a string format like when we alert a variable? The same formatted way I want to display an object. 回答1: If you want to print the object for debugging purposes, use the code: var obj = {prop1: 'prop1Value', prop2: 'prop2Value', child: {childProp1: 'childProp1Value'}} console.log(obj) will display: Note: you must only log the object. For example, this won't work: console.log('My object : ' + obj) Note ' : You can also use a comma in the log

问题 How do I display the content of a JavaScript object in a string format like when we alert a variable? The same formatted way I want to display an object. 回答1: If you want to print the object for debugging purposes, use the code: var obj = {prop1: 'prop1Value', prop2: 'prop2Value', child: {childProp1: 'childProp1Value'}} console.log(obj) will display: Note: you must only log the object. For example, this won't work: console.log('My object : ' + obj) Note ' : You can also use a comma in the log

问题 How do I display the content of a JavaScript object in a string format like when we alert a variable? The same formatted way I want to display an object. 回答1: If you want to print the object for debugging purposes, use the code: var obj = {prop1: 'prop1Value', prop2: 'prop2Value', child: {childProp1: 'childProp1Value'}} console.log(obj) will display: Note: you must only log the object. For example, this won't work: console.log('My object : ' + obj) Note ' : You can also use a comma in the log

问题 This question already has an answer here : Why does {} == false throw an exception? (1 answer) Closed 3 years ago . On my free time, I was just playing with js console, I got an unexpected error: js> [] == {} false js> {} == [] typein:5: SyntaxError: syntax error: I tried with === : js> [] === {} false js> {} === [] typein:9: SyntaxError: syntax error: Am thinking wrong here? I tested this with Firefox, Chrome and jscore. 回答1: That's because in the second case, {} is interpreted as a code

问题 I need to replace array of object in javascript. Here is my data variable and I want to update data variable const data = [{name: "poran", id: "22"}]; Expected value: data = [{value: "poran", age: "22"}]; How can I replace array of object? 回答1: You can create a new array with the use of .map() and some Object Destructuring: const data = [{name:"poran",id:"22"}]; const result = data.map(({ name:value , id:age }) => ({value, age})); console.log(result); 回答2: You can use a .forEach() loop over

问题 People! It's my first question here as junior frontend dev. I have function (https://jsfiddle.net/kmjhsbt9/) which transforms a flat array like this : const filePaths = [ 'src/lib/git.js', 'src/lib/server.js', 'build/css/app.css', 'externs/test/jquery.js', ]; into object tree like this: [ src: { lib: { git.js: 'file', server.js: 'file', } }, build: { css: { app.css: 'file' } } ..... ] Please, help me to understand how I can rewrite the function so that it outputs the result in this format: [