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callbacks.js
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87 lines (72 loc) · 1.9 KB
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/* eslint-disable */
const firstItem = (arr, cb) => {
// firstItem passes the first item of the given array to the callback function.
cb(arr[0]);
};
const getLength = (arr, cb) => {
// getLength passes the length of the array into the callback.
cb(arr.length);
};
const last = (arr, cb) => {
// last passes the last item of the array into the callback.
cb(arr[arr.length-1]);
};
const sumNums = (x, y, cb) => {
// sumNums adds two numbers (x, y) and passes the result to the callback.
cb(x + y);
};
const multiplyNums = (x, y, cb) => {
// multiplyNums multiplies two numbers and passes the result to the callback.
cb(x*y);
};
const contains = (item, list, cb) => {
// contains checks if an item is present inside of the given array/list.
// Pass true to the callback if it is, otherwise pass false.
for(let i = 0; i < list.length; i++){
if(list[i] === item){
cb(true);
}
else {
cb(false);
}
}
};
/* STRETCH PROBLEM */
const removeDuplicates = (array, cb) => {
// removeDuplicates removes all duplicate values from the given array.
// Pass the duplicate free array to the callback function.
// Do not mutate the original array.
let array2 = [];
for (let i = 0; i < array.length; i++) {
if (!array2.includes(array[i])) {
array2.push(array[i]);
}
}
cb(array2);
};
/* eslint-enable */
module.exports = {
firstItem,
getLength,
last,
sumNums,
multiplyNums,
contains,
removeDuplicates,
};
const pairs = (obj) => {
// Convert an object into a list of [key, value] pairs.
// http://underscorejs.org/#pairs
// return Object.entries(obj);
const objKeys = Object.keys(obj);
const objValues = Object.values(obj);
const arrOfPairs = [];
let pair = [];
for (let i = 0; i < objKeys.length; i++) {
pair.push(objKeys[i], objValues[i]);
arrOfPairs.push(pair);
pair = [];
}
// returns list of tuples
return arrOfPairs;
};