lodash

问题 My collection looks like this. var list = [{id:'12345', sequence:null}, {id:'12346', sequence:null}, {id:'12347', sequence:null}, {id:'12348', sequence:1}, {id:'12348', sequence:2}, {id:'12349', sequence:1}, {id:'12349', sequence:1}]; I am trying to get a unique list so that object with same id AND sequence will only return one of the objects (we have 2 here- {id:'12349', sequence:1}) my code var uniqueList = _.uniq(list, function(obj) { return obj.id && obj.sequence; }); can we use lodash

问题 Is it possible to loop through the properties in a JavaScript object? For instance, I have a JavaScript object defined as this: myObject.options = { property1: 'value 1', property2: 'value 2' }; Properties will get dynamically added to this object. Is there a way for me to just loop through and do a check if a property exists? If so, how? 回答1: Yes you can and lodash is not needed... i.e. for (var key in myObject.options) { // check also if property is not inherited from prototype if (myObject

问题 Other than stating "transform is a more powerful alternative to reduce", I can find no documentation of what the differences are. What are the differences between transform and reduce in lodash (Other than it being 25% slower)? 回答1: I like to dive into the source code before I pull in utilities. For lo-dash this can be difficult as there is a ton of abstracted internal functionality in all the utilities. transform source reduce source So the obvious differences are: If you dont specify the

问题 I'm sure it's somewhere inside the LoDash docs, but I can't seem to find the right combination. var users = [{ id: 12, name: Adam },{ id: 14, name: Bob },{ id: 16, name: Charlie },{ id: 18, name: David } ] // how do I get [12, 14, 16, 18] var userIds = _.map(users, _.pick('id')); 回答1: Since version v4.x you should use _.map: _.map(users, 'id'); // [12, 14, 16, 18] this way it is corresponds to native Array.prototype.map method where you would write (ES2015 syntax): users.map(user => user.id);

问题 I have an array of objects. I want to find by some field, and then to change it: var item = {...} var items = [{id:2}, {id:2}, {id:2}]; var foundItem = items.find(x => x.id == item.id); foundItem = item; I want it to change the original object. How? (I dont care if it will be in lodash too) 回答1: You can use findIndex to find the index in the array of the object and replace it as required: var item = {...} var items = [{id:2}, {id:2}, {id:2}]; var foundIndex = items.findIndex(x => x.id == item

问题 So I'm using Vue to filter a list. This consists of the following structure (Baum Hierarchy if anyone is interested): [ { "id": 61, "created_at": "2016-11-23 22:07:10", "updated_at": "2016-12-15 19:44:56", "parent_id": null, "lft": 107, "rgt": 116, "depth": 0, "name": "Quia eos voluptas molestiae ut cum.", "slug": "consequatur-voluptatum-dolores-non-perferendis-possimus", "order_column": null, "belongs_to": null, "children": [ { "id": 57, "created_at": "2016-11-23 22:07:10", "updated_at":

问题 Have an object a1 = [{name:'x',age:21, addr:[{flat:1,add:'xyz'},{flat:2,add:'xsr'}]}, {name:'y',age:22, addr:[{flat:3,add:'xyz1'},{flat:4,add:'xsr1'}]] Desired output: [{name:'x',age:21, addr:{flat:1,add:'xyz'}}, {name:'x',age:21, addr:{flat:2,add:'xsr'}}, {name:'y',age:22, addr:{flat:3,add:'xyz1'}, {name:'y',age:22, addr:{flat:4,add:'xsr1'}] Please suggest! I am trying to accomplish this using lodash/underscore. 回答1: Map every item in the original array to a new array, with a number of items

问题 So I have an array of items like this: items = [ { amount: 2, name: 'bike' }, { amount: 1, name: 'boat' }, { amount: 3, name: 'bike' } ] Now, I would like to merge this array so that there would be no duplicates of bike and still know how many bikes there are in total. so my result array would look like this: items = [ { amount: 5, name: 'bike' }, { amount: 1, name: 'boat' } ] In order to keep my code short I have been advised using lodash and I've been looking at the different ways to merge

问题 Is there a function that lets me concat several arrays, with delimiters between them (the delimiters are also arrays), similarly to how join works but not restricted to strings? The function can be standard JS or part of a major library such as lodash (which is why it's referenced in the tags). Here is an example of usage: let numbers = [[1], [2], [3]]; let result = _.joinArrays(numbers, [0]); console.log(result); //printed: [1, 0, 2, 0, 3] This is analogous to: let strings = ["a", "b", "c"];

问题 Is there a function that lets me concat several arrays, with delimiters between them (the delimiters are also arrays), similarly to how join works but not restricted to strings? The function can be standard JS or part of a major library such as lodash (which is why it's referenced in the tags). Here is an example of usage: let numbers = [[1], [2], [3]]; let result = _.joinArrays(numbers, [0]); console.log(result); //printed: [1, 0, 2, 0, 3] This is analogous to: let strings = ["a", "b", "c"];