javascript-objects

问题 I have an object where a few of the keys are nested single level hashes. In this example only b is nested. const j = { a: 'A', b: { bb: 'BB', bbb: 'BBB', }, c: 'C' }; Question What I am looking for is a way to loop over the object and if a key is a nested object, then print its keys instead. a bb bbb c Does anyone know how to do that? 回答1: You can do this recursively: function printKeys(obj) { for (const [key, val] of Object.entries(obj)) { if (typeof val === "object") { printKeys(val); }

问题 I have an object like this, { id: '1', displaName: 'A', children: [ { id: '2', displayName: 'B', children: [ { id: '3', displayName: 'C', children: [ //More nested array here ] } ] }] } I just want to change key displayName with label so that my object will look like this, { id: '1', label: 'A', //change key displayName => label children: [ { id: '2', label: 'B', //change key displayName => label children: [ { id: '3', label: 'C', //change key displayName => label children: [ //More nested

问题 I am trying to make a Proxy object of Image to trap properties but even with an empty handler I get an error message. TypeError: Argument 1 of Node.appendChild does not implement interface Node. The proxy object is suppose to act as the target object so this baffles me a little. As far as I understand you should be able to do this with DOM nodes as well (?). Also : I cannot start loading the image and have the onload handler triggered when setting the src property. How should I use the Proxy

问题 I'm trying to make a circlular bar progress using html canvas and javascript and i've suceed until I've add a loop with setInterval, since that I'm stuck... I tried to target the problem putting console.log() in all the elements I use to do the loop, but I can't get through why my loop is working in the console but the cirlce doesn't appear. Can anyone help me. I will be very grateful. Thank you in advance. here is my code : class GreyCircle { constructor(x, y, radius) { this.posX = x; this

问题 I have an object like var person = {'id':null, 'name':'John Doe'} After inserting the object value into the database, I will get another object from the server: var personInDB = {'id':1234, 'name':'John Doe'} I have used angular.merge to use updated the value of person with that of personInDB . But, I want to empty person object before applying angular.merge , so that I only get the values in database. I don't want to assign new empty object to person as that will break data-binding in

问题 I have an object like var person = {'id':null, 'name':'John Doe'} After inserting the object value into the database, I will get another object from the server: var personInDB = {'id':1234, 'name':'John Doe'} I have used angular.merge to use updated the value of person with that of personInDB . But, I want to empty person object before applying angular.merge , so that I only get the values in database. I don't want to assign new empty object to person as that will break data-binding in

问题 I am developing an application where I need to implement simple search functionality, so I have this large object with child objects and arrays. Usually I access data in that object like this: list[id][day][show].title but now I need to check if that title is equal to some input value, so I created this function: getSimilarShows = (allShows, expectedShow) => { const titles = [] Object.values(Object.values(allShows)).map((days) => Object.values(days).map((items) => Object.values(items).map(

问题 I am developing an application where I need to implement simple search functionality, so I have this large object with child objects and arrays. Usually I access data in that object like this: list[id][day][show].title but now I need to check if that title is equal to some input value, so I created this function: getSimilarShows = (allShows, expectedShow) => { const titles = [] Object.values(Object.values(allShows)).map((days) => Object.values(days).map((items) => Object.values(items).map(

问题 I am developing an application where I need to implement simple search functionality, so I have this large object with child objects and arrays. Usually I access data in that object like this: list[id][day][show].title but now I need to check if that title is equal to some input value, so I created this function: getSimilarShows = (allShows, expectedShow) => { const titles = [] Object.values(Object.values(allShows)).map((days) => Object.values(days).map((items) => Object.values(items).map(

问题 I am developing an application where I need to implement simple search functionality, so I have this large object with child objects and arrays. Usually I access data in that object like this: list[id][day][show].title but now I need to check if that title is equal to some input value, so I created this function: getSimilarShows = (allShows, expectedShow) => { const titles = [] Object.values(Object.values(allShows)).map((days) => Object.values(days).map((items) => Object.values(items).map(