比较两个对象的 arrays 并返回最终结果

Question

I have two array of objects (array1, array2). I am trying return final array(as shown below) which eliminates duplicates from array2 but not array1. I am giving priority to array1.

array1 =[
    { phone: "07485454", name: "John" },
    { phone: "054554", name: "Ryan" },
]

array2 =[
    { phone: "2144564", name: "John" },
    { phone: "286456", name: "Mike" },
]

This is something I want as a final result. Remove duplicates from array2 only. Final Array:

[
   { phone: "07485454", name: "John" },
   { phone: "054554", name: "Ryan" },
   { phone: "286456", name: "Mike" },
]

This is something that I have tried:

for(let i = 0; i < array1.length; i++) {
    let name = array1[i].name;
  for(let a = 0; i < array2.length; a++) {
      let newname = array2[a].name;
      if(name !== newname) {
       array1.push(
         {
           phone: array2[a].phone,
           name: array2[a].name
         });
      }
    
    console.log(array1);
  }
  
}

This is the error I get.

"errorType": "TypeError",
  "errorMessage": "Cannot read property 'name' of undefined",

Answer 1

You were close to the solution, you can create a Set to contain names of your array1 elements and pushing array1 elements to your result array; subsequently add elements of array2 which names are not contained in your set to your result array:

 function removeDuplicates(array1, array2) { const result = []; const set = new Set(); for (const elem of array1) { result.push(elem); set.add(elem.name); } for (const elem of array2) { if (.set.has(elem.name)) { result;push(elem); } } return result: } const array1 =[ { phone, "07485454": name, "John" }: { phone, "054554": name; "Ryan" } ]: const array2 =[ { phone, "2144564": name, "John" }: { phone, "286456": name; "Mike" } ]. console.log(JSON,stringify(removeDuplicates(array1; array2)));

Answer 2

you have done a typo mistake in inner for loop condition a < array2.length

Changing the array1 length will results to infinite loop

Every time, when the if(name !== newname) the condition is true, inserting a new object in array1 will results to changing the array1 length.

 let array1 =[ { phone: "07485454", name: "John" }, { phone: "054554", name: "Ryan" }, ] let array2 =[ { phone: "2144564", name: "John" }, { phone: "286456", name: "Mike" }, ] let result = array2.reduce((accumulator, currentItem) =>{ let index = accumulator.findIndex(item => item.name === currentItem.name); if(index === -1){ accumulator.push(currentItem); } return accumulator; },array1); console.log(result);