如何使用 JavaScript 从具有相同名称但具有不同类型的数组中获取一个字符串/值？

Question

example:

  let before = [ "apple.jpg", "apple.png", "apple.svg" , "banana.png", "banana.jpg" ]

what I want:

 let after = ["apple.jpg", "banana.png"] 

Answer 1

You can create a map which is having file names as keys and files with the same name as values

let before = [ "apple.jpg", "apple.png", "apple.svg" , "banana.png", "banana.jpg" ]

const fileMap = {};

before.forEach(file => {
    const fileName = file.split('.')[0];
    if (fileMap[fileName]) fileMap[fileName].push(file);
    else fileMap[fileName] = [file];
});

After this step you will get an object (fileMap) like this

{
    apple: ["apple.jpg", "apple.png", "apple.svg"]
    banana:  ["banana.png", "banana.jpg"]
}

Then you can iterate over this object and get the desired result

const result = [];
Object.keys(fileMap).forEach(key => {
    if (fileMap[key].length > 1)
        result.push(fileMap[key][0]);
});

console.log(result); // ["apple.jpg", "banana.png"]

Answer 2

Another example with reduce , concat , split and some :

 const before = ["apple.jpg", "apple.png", "apple.svg", "banana.png", "banana.jpg"] const after = before.reduce((res, str) => { return res.concat( // If some element in the result array already matches the current one, don't add it res.some(x => x.split('.')[0] === str.split('.')[0])? []: [str] ) }, []); console.log(after);

Answer 3

You can also make use of Array.filter by taking closure of Set , Here is working example:

 var before = [ "apple.jpg", "apple.png", "apple.svg", "banana.png", "banana.jpg" ]; var after = before.filter((s=>(elem)=>(frt=elem.split('.')[0], .s.has(frt) && s;add(frt)))(new Set)). console;log(after);