how do i find a value in an array of objects?

This should do.

You don’t have to loop through the array, you can use build-in functions like map, some and filter to achieve this.

var data = [
   {id:1,first_name:'John',last_name:'Doe',age:20,birth:'1992-01-12'},
   {id:1,first_name:'John',last_name:'Bal',age:20,birth:'1992-01-12'},
   {id:2,first_name:'Blaan',last_name:'Adey',age:35,birth:'2001-04-16'}
];

var searchColumn = ['first_name','last_name','birth'];

var search = (searchParam) => {
    // map here applies the function  (value) => searchColumn.some(property => value[property] === searchParam) ? value : null
    // over every value in the array & some loops through every value in the search column
    // looking for an object where one of the properties specified in searchColumn has a value that matches our search parameter
    return data.map(value => searchColumn.some(property => value[property] === searchParam) ? value : null)
        .filter(result => !!result); // here we use filter to remove the null values mapped in the map function
}

search('John');
// result -> [{id:1,first_name:'John',last_name:'Doe',age:20,birth:'1992-01-12'},
//         -> {id:1,first_name:'John',last_name:'Bal',age:20,birth:'1992-01-12'}]

UPDATE: As suggested, an better solution:

var search = (searchParam) => {
    return data.filter(value => !!searchColumn.some(property => value[property] === searchParam));
}