Find element in map-CodePudding

I have a map of objects:

"0": {
    key: 'id',
    value: {
        name: "eval"
        // other variables
    }
},
"1": {
    key: 'id',
    value: {
        name: "help"
        // other variables
    }
} // and so on

I need to find an element in map that's name variable is eqaul to "eval". What's the easiest way to do this?

CodePudding user response：

If "map" is an array

let arr = [{key:'id', value:{ name:'eval' }}]
let item = arr.find(el => el.value.name == 'eval')

If "map" is an object

let obj = {0:{key:'id', value:{ name:'eval' }}}
let item = Object.values(obj).find(el => el.value.name == 'eval')

CodePudding user response：

Use <Array>.from to convert map values to array and after filter what you want.

const map = new Map();

map.set(0, {
  key: 'id',
    value: {
      name: "eval"
    }
});

map.set(1, {
  key: 'id',
    value: {
      name: "help"
    }
});

const result = Array.from(map.values())
  .filter(x => x.value.name === 'eval')[0];
  
console.log(result);

CodePudding user response：

The good old forEach Loop can do it too.

const data = [{
    key: 'id',
    value: {
        name: "eval"
        // other variables
    }
},
{
    key: 'id',
    value: {
        name: "help"
        // other variables
    }
}]

let res = [];
data.forEach((el) => {
  if (el.value.name === "eval") {
    res.push(el);
  }  
})

console.log(res)

CodePudding user response：

You can do this

const tmp = {
  "0": {
    key: "id",
    value: {
      name: "eval"
      // other variables
    }
  },
  "1": {
    key: "id",
    value: {
      name: "eval"
      // other variables
    }
  }
};

function findEval(obj, target) {
    const elem = Object.keys(obj).filter(key => tmp[key].value.name === target);
    return elem.map(e => obj[e]);
}
console.log(findEval(tmp, 'eval'))

but better use lodash Find property by name in a deep object

CodePudding user response：

simple and best solution

const tmp = {
  "0": {
    key: "id",
    value: {
      name: "eval"
      // other variables
    }
  },
  "1": {
    key: "id",
    value: {
      name: "eval"
      // other variables
    }
  }
};

function findEval(obj, target) {
    for (var i=0; i < Object.keys(obj).length; i  ) {
        if (obj[i].value.name === target) {
            return obj[i].value.name;
        }
    }
}
console.log(findEval(tmp, 'eval'))