Simple ES6 reference with useful methods

useful-javascript-snippets.js

const orders = [500, 30, 99, 15, 223];

/**
 * Reduce
 * @return a single value as output
 */
const total = orders.reduce((acc, cur) => acc + cur)

/**
 * Map
 * @return an array as output
 */
const withTax = orders.map(v => v * 1.1)

/**
 * Filter
 * @return an array as output
 */
const highValue = orders.filter(v => v > 100);

/**
 * Every
 * @return a single boolean output
 */
const everyValueGreaterThan50 = orders.every(v => v > 50)
const everyValueGreaterThan10 = orders.every(v => v > 10)

/**
 * Some
 * @return a single boolean output
 */
const someValueGreaterThan500 = orders.some(v => v > 500)

/**
 * Some
 * @returns true
 */
const someValueGreaterThan10 = orders.some(v => v > 10)

/**
 * Variable Evaluation
 * Reference:
 * https://stackoverflow.com/questions/2647867/how-can-i-determine-if-a-variable-is-undefined-or-null
 */

if (typeof EmpName != 'undefined' && EmpName) {
/* will evaluate to true if value is not:
    null
    undefined
    NaN
    empty string ("")
    0
    false
*/

/**
 * Remove duplicate from array
 * Reference:
 * https://stackoverflow.com/questions/2647867/how-can-i-determine-if-a-variable-is-undefined-or-null
 */

//from simple array
var arr = [1,2,3,4,5,1,1,2];
const remDuplicateWithSet = (data) => {
    return [...new Set(data)]
}
console.log(remDuplicateWithSet(arr));

// from array of objects
var arrayObj = [
    {
        'id':'1',
        'name':'iri1',
    },
    {
        'id':'2',
        'name':'iri2',
    },
    {
        'id':'3',
        'name':'iri3',
    },
    {
        'id':'1',
        'name':'iri1',
    },
    {
        'id':'3',
        'name':'iri1',
    },
    {
        'id':'3',
        'name':'iri1',
    },
    ];

function removeDuplicates(array, key) {
    return array.filter((obj, index, self) =>
        index === self.findIndex((el) => (
            el[key] === obj[key]
        ))
    )
}
console.log(removeDuplicates(arrayObj, 'id'))
    
/**
 * Add and remove elements on arrays
 */ 
addAndRemove() {
    let A = [
      {
        id: 1,
      },
      {
        id: 2,
      },
      {
        id: 3,
      },
    ];
    const B = [
      {
        id: 1,
      },
      {
        id: 4,
      },
      {
        id: 5,
      },
    ];
    // add
    B.forEach((obj) => {
      if (
        !A.find((x) => {
          return x.id == obj.id;
        })
      ) {
        A.push(obj);
      }
    });

    // remove
    A.forEach((obj, index, array) => {
      if (
        !B.find((x) => {
          return x.id == obj.id;
        })
      ) {
        array.splice(index, 1);
      }
    });
  } 

/**
 * Some References:
 * Array Docs: https://www.tutorialspoint.com/es6/es6_arrays.htm
 */