How to check the value of an associative array using by TypeScript?

Question

I want to get longest name value in bellow associative array of TypeScript. Some objects in array have child array. I want to check all nest array.

    interface Tree {
    id: string
    name: string
    child?: Tree[]
}
const treeArray: Tree[] = [
    {
        id: "test", name: "test1", child: [
            { id: "Test#2", name: "@2ndtest" },
            {
                id: "test#2", name: "2ndtest", child: [
                    { id: "Test#2#3", name: "@3rdtestTestTest" },
                ]
            }
        ]
    },
    { id: "testtest", name: "testtest2" }
]

So, my expected out put was like below.

{ id: "Test#2#3", name: "@3rdtestTestTest" }

I made code below get output.

    const getLongestNameObjectInTreeArray = (value: Tree[]) => {
    let getObj: Tree = { id: "", name: "" }
    let longestName = 0
    value.forEach((v) => {
        let nameLength = v.name.length
        if (<any>nameLength > longestName) {
            longestName = <any>nameLength
            getObj = { id: v.id, name: v.name }
        }
    })
    return getObj
}
console.log(getLongestNameObjectInTreeArray(treeArray))

but this code output was { id: 'testtest', name: 'testtest2' }

The problem is my function is not loop nest array. Does anyone advise me,please?

jeremy302 · Accepted Answer · 2021-04-19 06:48:22Z

2

You could use recursion like this:

function getLongestName(tree:Tree):string{
    let treeName = tree.name;
    let longestChildName = tree.child?.reduce((a,b)=>{
        let bName=getLongestName(b);
        return (a.length>bName.length)?a:bName
    },treeName)??treeName
    return longestChildName
}
function getLongestNameArray(trees:Tree[]):string{
    return trees.map(tree=>getLongestName(tree)).reduce((nameA,nameB)=>nameA.length>nameB.length?nameA:nameB,"");
}
console.log(getLongestNameArray(treeArray))

answered Apr 19, 2021 at 6:48

jeremy302

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Comments

Nimna Perera · Accepted Answer · 2021-04-19 06:33:54Z

1

As you are using recursive structure in your interface, Therefore you have to use recursive function to solve your problem.

interface Tree {
    id: string
    name: string
    child?: Tree[]
}

const treeArray: Tree[] = [
    {
        id: "test", name: "test1", child: [
            { id: "Test#2", name: "@2ndtest" },
            {
                id: "test#2", name: "2ndtest", child: [
                    { id: "Test#2#3", name: "@3rdtestTestTest" },
                ]
            }
        ]
    },
    { id: "testtest", name: "testtest2" }
]

const getLongestNameObjectInTreeArray = (arr: Tree[])  => {
    let longestlength = 0
    let output: Tree;
    arr.forEach(e => {
        if (e.name.length > longestlength) {
            longestlength = e.name.length;
            output = { id: e.id, name: e.name };
        }

        if (e.child) {
            const childOutput = getLongestNameObjectInTreeArray(e.child);
            if (childOutput.name.length > longestlength) {
                longestlength = childOutput.name.length;
                output = { id: childOutput.id, name: childOutput.name };
            }
        }
    });

    return output;
}

console.log(getLongestNameObjectInTreeArray(treeArray))

answered Apr 19, 2021 at 6:33

Nimna Perera

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1 Comment

drunkdolphin Over a year ago

Awesome!! I really really appreciate your answer!! I don't have any ideas to use recursive function. I clearly understand!! Thank you so much!!

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