Demonstration of some common js array methods.

js-array-methods

/* JavaScript Array Methods */


let emojis; 
function resetEmojis() {
  emojis = ["one", "two", "three", "four"];
}

// Instantiate emojis array
resetEmojis();



/**
 *
 * @param {Function} fn - A callback function to execute
 */
function execAndLog(fn, fnName) {
  console.log("Emoji array before ▶ ", emojis);
  console.log(`${fnName} ▶ `, fn());
  console.log("Emojis array after ▶ ", emojis, "\n\n");
}




/** Below methods doesn't modify the original array */

// Concatenate two or more arrays
execAndLog(() => emojis.concat([1, 2]), "emojis.concat([1, 2])");

// Convert an array to a string
execAndLog(() => emojis.join("-"), "emojis.join('-')");

// Get shallow copy of a portion of an array
execAndLog(() => emojis.slice(0, 2), "emojis.slice(0, 2)");

// Get index of an array element
execAndLog(() => emojis.indexOf("three"), "emojis.findIndex('three')");

// Check if an element exists in an array
execAndLog(() => emojis.includes("none"), "emojis.includes('none')");

// Find a specific element in an array
execAndLog(() => emojis.find((el) => typeof el === "string"), "emojis.find(/* El of type string */)");

// Find index of a specific element in an array
execAndLog(() => emojis.findIndex((el) => typeof el === "string"), "emojis.find(/* Index of el of type string */)");

// Create a new and modified array
execAndLog(() => emojis.map((el) => el + 'test'), "emojis.map(/* Add 'test' to all elements */)")



/** There are more but I couldn't add them because another problem set was given */