You can use .map var data = [ {“key”:”fruit”,”value”:”apple”}, {“key”:”color”,”value”:”red”}, {“key”:”location”,”value”:”garden”} ]; var result = data.map(function (e) { var element = {}; element[e.key] = e.value; return element; }); console.log(result); also if you use ES2015 you can do it like this var result = data.map((e) => { return {[e.key]: e.value}; }); Example
Your question seems to be about why we can’t access array and array-like elements using the dot notation like this: const v = a.0; It’s described in the ECMAScript specification: The dot notation is explained by the following syntactic conversion: MemberExpression . IdentifierName And identifiers may not start with a digit as described here: IdentifierName … Read more
For more generic advice on debugging this kind of problem MDN have a good article TypeError: “x” is not a function: It was attempted to call a value like a function, but the value is not actually a function. Some code expects you to provide a function, but that didn’t happen. Maybe there is a … Read more
This is good for shallow cloning. The object spread is a standard part of ECMAScript 2018. For deep cloning you’ll need a different solution. const clone = {…original} to shallow clone const newobj = {…original, prop: newOne} to immutably add another prop to the original and store as a new object.
A simple map with object spread syntax will do it. Instead of object spread, Object.assign can also be used. Assign unto a new empty object in order to avoid mutating the existing objects. var array1 = [ { name: “lang”, value: “English” }, { name: “age”, value: “18” } ]; var array2 = [ { … Read more
A simple self-calling function can do it. function removeMeta(obj) { for(prop in obj) { if (prop === ‘$meta’) delete obj[prop]; else if (typeof obj[prop] === ‘object’) removeMeta(obj[prop]); } } var myObj = { “part_one”: { “name”: “My Name”, “something”: “123”, “$meta”: { “test”: “test123” } }, “part_two”: [ { “name”: “name”, “dob”: “dob”, “$meta”: { … Read more
Because name is a non-standard, non-writable property of function objects. Function declarations and named function expressions are named, while you have an anonymous function expression whose name is “”. You probably wanted a plain object: var person = { name: “John Smith”, age: 21, profession: “Web Developer” };
One way to do it is through object destructuring and an arrow function: let source = { x: 120, y: 200, z: 150, radius: 10, color: ‘red’, }; let result = (({ x, y, z }) => ({ x, y, z }))(source); console.log(result); The way this works is that the arrow function (({ x, y, … Read more
It’s the way v8 handles associative arrays. A known issue Issue 164 but it follows the spec so is marked ‘working as intended’. There isn’t a required order for looping through associative arrays. A simple workaround is to precede number values with letters e.g: ‘size_7’:[‘9149′,’9139’] etc. The standard will change in the next ECMAScript spec … Read more
This is easily done with the Array.prototype.map() function: var keyArray = objArray.map(function(item) { return item[“key”]; }); If you are going to do this often, you could write a function that abstracts away the map: function pluck(array, key) { return array.map(function(item) { return item[key]; }); } In fact, the Underscore library has a built-in function called … Read more