Ablestate Corhort 1 javascript session

Array objects

/**
 * Array methods
 */

/**
 * array.concat(value1, value2,...valueN)
 * Concatinates two or more arrays and returns a new array
 * It also accepts values of different data types e.g strings, numbers etc
 */
console.clear();
let districts1 = ["kampala", "Jinja", "Mukono"];
let districts2 = ["Mbarara", "Masaka"];

//concate two arrays
let districts3 = districts1.concat(districts2);
console.log(districts3);

//concate other valaues to the array 
let mixed = districts3.concat("Lwengo", 100, { name: "David"});
console.log(mixed);

/**
 * array.every(callbacks[, thisObject])
 * It returns true id every elements in the array satisifies the testing function. The testing function is passed as a callback.
 */

const TEST_IF_STRING = element => typeof element === 'string' ? true : false
/* const TEST_IF_STRING = element => {
   if (typeof elemenent === 'string') return true
    return false;
}
*/
console.clear();

// const TEST_IF_STRING = (element) => {
//   if (typeof element === 'string') return true;
//    return false;
// }

let valueOfevery = districts1.every(TEST_IF_STRING)
 console.log(valueOfevery);

valueOfevery = mixed.every(TEST_IF_STRING)
console.log(valueOfevery);

valueOfevery = mixed.every(function (elements){
  if (typeof element === "string") return true;
return false;
});
console.log("");
console.log(valueOfevery);

valueOfevery = mixed.every((element) => typeof element === "string" ? true : false);
console.log();
console.log(valueOfevery);

valueOfevery = districts2.every((element) => typeof element === "string" ? true : false);
console.log();
console.log(valueOfevery);

/**
 * array.filter(callbacks[, thisobject])
 * Returns a new array containing the elements that satisify the conditions of the callbacks method
 */

 const RETURN_NUMBERS = element => typeof element === 'number' ? true : false

let getNumbers = mixed.filter(RETURN_NUMBERS)
console.log(getNumbers);

const RETURN_STRING = element => typeof element === `string` ? true : false

let getString = mixed.filter(RETURN_STRING)
console.log(getString);

// const RETURN_OBJECT = (element) => type element === "object" ? true : false;

// let getObject  = mixed.filter(RETURN_OBJECT)
// console.log(getObject)

let getObject  = mixed.filter((element) => typeof element === `object` ? true : false);
console.log(getObject)

/**
 * array.forEach(callback[, thisObject])
 * It calls a callback function for each element in the array and returns undefined
 */
console.clear();
 const DESCRIBE_ELEMENT = (element) => 
   console.log(`${typeof element} : ${element}`);

//console.log(mixed.forEach(DESCRIBE_ELEMENT));

let holdObject = [];

mixed.forEach((element) => {
  if ( typeof element === "object") holdObject.push(element);
});

console.log(holdObject);

mixed.forEach((element) => {
   if (typeof element === "object") mixed.pop();
});

console.log(mixed)

/**
 * array.join(separator)
 * Its joins array elements and returns a string
 * Default the separator is a comma.
 */

let districtString = districts1.join(", ");
console.log(districtString)
// console.log(districts1)
// for (let num = 0; num < districts1.length; num++){
//    console.log(`${num} : ${districts1[0],districts1[1]}`)
// }

districtString = districts1.join(" | ");
console.log(districtString)

/**
 * array.map(callback[, thisObject])
 * It invokes a callback for each element in the array and returns an array
 */

const DECORATE_ELEMENT = (element) => {
  if ( typeof element !== "object") return `- ${element} -`;
};
let decoratedElements = mixed.map(DECORATE_ELEMENT);
console.log(mixed); //Test if it mutates the orginal array
console.log(decoratedElements);

const generatedHTMLOptions = (element) => {
  if ( typeof element !== "object") 
  return `<options value="${element}"> ${element} </options>`;
};

let htmlOptions = mixed.map(generatedHTMLOptions)
console.log(htmlOptions);