在JavaScript中从数组中查找索引号

Question

I would like to loop through an array of elements and find the index # of the one that matches certain criteria. Take the following array:

services: [
  { _id: <ObjectId>,
    name: "initiating"
  },
  { _id: <ObjectId>,
    name: "evaluating"
  },
  { _id: <ObjectId>,
    name: "servicing"
  },
]

How would I loop through this array and pull out the array index # of the object where the property "name" is equal to "evaluating" (ie - array element #1)?

Answer 1

Try Array.prototype.findIndex :

 const services = [ { _id: 1, name: "initiating" }, { _id: 2, name: "evaluating" }, { _id: 3, name: "servicing" }, ]; console.log( services.findIndex(({ name }) => name === 'evaluating') ); 

Answer 2

 let services = [{ _id: 0, name: "initiating" }, { _id: 1, name: "evaluating" }, { _id: 2, name: "servicing" }, ] let selected = services.findIndex(service => service.name == "evaluating") console.log(selected) 

Answer 3

 let services = [{ _id: 0, name: "initiating" }, { _id: 1, name: "evaluating" }, { _id: 2, name: "servicing" }, ]; let index = services.findIndex(item => item.name === "evaluating"); document.write(index); 

This will return the index after searching through the each object's name property and comparing it to "evaluating".

Answer 4

You may use .reduce() :

 var services = [ { _id: '<ObjectId>', name: "initiating" }, { _id: '<ObjectId>', name: "evaluating" }, { _id: '<ObjectId>', name: "servicing" }, ]; var idx = services.reduce((x, ele, idx) => (ele.name=='evaluating') ? idx : x, -1); console.log(idx);