Code examples javascript ebook

Code examples javascript ebook

• 1.
  How to removeand update array items const arr1 = ['FIRST','Laurence','Svekis',100,false]; const arr2 = ['SECOND',2332,true,'Hello','Svekis',400,false]; const arr3 = arr1.concat(arr1,arr2); const arr4 = arr1; arr2.push(arr1); console.log(arr2); console.log(arr3); Array.prototype.push.apply(arr1,arr2); console.log(arr1); arr2.push('NEW ITEM'); Course Source Code by Laurence Svekis https://basescripts.com/
• 2.
  arr1.push('Arr 1 New'); //deletearr1[12]; //delete arr2[7]; //arr1.length = 0; arr1.splice(12,1,'REMOVED','SECOND'); arr2.splice(3); console.log(arr1); console.log(arr2); console.log(arr3); console.log(arr4); Comparing Data Type and automatic conversion of Data Types let a = [10]; let b = 10; let c = "10"; if(a == b) console.log(`${a} == ${b}`); if(a == c) console.log(`${a} == ${c}`); if(a === b) console.log(`${a} === ${b}`); Course Source Code by Laurence Svekis https://basescripts.com/
• 3.
  if(a === c)console.log(`${a} === ${c}`); if(a != b) console.log(`${a} != ${b}`); if(a != c) console.log(`${a} != ${c}`); if(a !== b) console.log(`${a} !== ${b}`); if(a !== c) console.log(`${a} !== ${c}`); let d = []; let e = 0; let f = false; let g = ''; let h = null; let i = undefined; let j = NaN; console.clear(); if(d == e) console.log(`D ${d} == ${e}`); if(e == f) console.log(`E ${e} == ${f}`); if(f == g) console.log(`F ${f} == ${g}`); if(g == h) console.log(`G ${g} == ${h}`); if(h == i) console.log(`H ${h} == ${i}`); if(i == j) console.log(`I ${i} == ${j}`); if(j == d) console.log(`J ${j} == ${d}`); if(g == d) console.log(`GD ${g} == ${d}`); Course Source Code by Laurence Svekis https://basescripts.com/
• 4.
  if(f == h)console.log(`FH ${f} == ${h}`); if(f == i) console.log(`FI ${f} == ${i}`); if(f == j) console.log(`FJ ${f} == ${j}`); console.clear(); if(!d) console.log(`D Yes ${d}`); if(!e) console.log(`E Yes ${e}`); if(!f) console.log(`F Yes ${f}`); if(!g) console.log(`G Yes ${g}`); if(!h) console.log(`H Yes ${h}`); if(!i) console.log(`I Yes ${i}`); if(!j) console.log(`J Yes ${j}`); if(d === e) console.log(`D ${d} === ${e}`); if(e === f) console.log(`E ${e} === ${f}`); if(f === g) console.log(`F ${f} === ${g}`); if(g === h) console.log(`G ${g} === ${h}`); if(h === i) console.log(`H ${h} === ${i}`); if(i === j) console.log(`I ${i} === ${j}`); if(j === d) console.log(`J ${j} === ${d}`); Object Construction with JavaScript Course Source Code by Laurence Svekis https://basescripts.com/
• 5.
  function FullName(firstName,lastName){ this.firstName =firstName; this.lastName = lastName; this.full = `${firstName} ${lastName}`; } const person1 = new FullName("Laurence","Svekis"); console.log(person1.full); const person2 = new FullName("John","Svekis"); console.log(person2.full); const person3 = new FullName("Mike","Smith"); console.log(person3.full); let val = `${person1.firstName} ${person1.lastName}`; console.log(val); JavaScript Immediately invoked functions coding examples (function(){ console.log('ready'); })(); (()=>{ console.log('ready arrow'); })(); Course Source Code by Laurence Svekis https://basescripts.com/
• 6.
  ((a=1,b=2,c=3)=>{ console.log(a,b,c); const val =a * b * c; console.log(val); })(5,6,7); Random Numbers and Random Array items const arr = []; const arr1 = []; for(let i=0;i<10;i++){ const val = ran(0,1000); arr.push(val.toString()); } for(let i=0;i<20;i++){ const ind = Math.floor(Math.random()*arr.length); const val = arr[ind]; console.log(ind,val); } function ran(min,max){ return Math.floor(Math.random()*(max-min+1))+min; } for(let i=1;arr1.push(i++)<50;); Course Source Code by Laurence Svekis https://basescripts.com/
• 7.
  console.log(arr1); const arr2 =arr.sort(); const arr3 = arr.reverse(); arr.sort(()=>{ return Math.random() - 0.5; }); console.log(arr[0]); arr.sort(()=>{ return Math.random() - 0.5; }); console.log(arr[0]); String Whitespace Cleaner and Remover String.prototype.cleaner = function(){ return this.replace(/s+/g,' ').trim(); } const myStr1 = " Hello World "; console.log(myStr1.cleaner()); let val = myStr1; val = trimMyString(val); console.log(val); document.querySelector('.output').textContent = val; Course Source Code by Laurence Svekis https://basescripts.com/
• 8.
  function trimMyString(str){ let val= str.replace(/s+/g,' ').trim(); //val = str.trimLeft(); //val = str.trimRight(); return val; } JavaScript Logical Conditions let val = 5; val = 6; if(val == 5) {fun1(1);} if(val == 5) fun1(2); val == 5 && fun1(3); val == 5 || fun1(4); if(val != 5) fun1(5); fun1(); let val2; val2 = val2 || 100; console.log(val2); function fun1(v=1){ v = v || 1; console.log(`Hello ${v}`); } Course Source Code by Laurence Svekis https://basescripts.com/
• 9.
  Array Map Examples constarr1 = [1,5,7,8,23,342,2,3,4]; const arr2 = arr1.map((val,ind,arr)=>{ console.log(val,ind,arr); return val * val; }) const arr3 = arr1.map(val => val*val); const arr4 = arr1.map(callbackFun); function callbackFun(val){ return val * val; } console.log(arr1); console.log(arr2); console.log(arr3); console.log(arr4); Array Method Includes const arr = ["Svekis","Laurence",1000,20,300,true,323,"Svekis"]; const arr1 = arr.map(String); console.log(arr1); const myInput = document.querySelector('input'); const btn = document.querySelector('button'); const output = document.querySelector('.output'); Course Source Code by Laurence Svekis https://basescripts.com/
• 10.
  btn.addEventListener('click',(e)=>{ const val =myInput.value; const result = arr1.includes(val); let message; if(result){ message= `${result} is found in the array content`; }else{ message = `${result} is NOT found`; } output.textContent = message; console.log(result); }) let val = arr.includes("Svekis"); console.log(val); val = arr.includes("Svekis",-1); console.log(val); JavaScript Serialization and deserialization const output = document.querySelector('.output'); const arr1 = ["Svekis","Laurence",1000,true]; const obj1 = { first : "Laurence", last : "Svekis", id : 1000, num : 55, mes : "Hello", boo : false Course Source Code by Laurence Svekis https://basescripts.com/
• 11.
  }; output.textContent = arr1; output.textContent= obj1; console.log(arr1); console.log(obj1); let val = JSON.stringify(obj1) val = JSON.stringify(arr1); console.log(val); output.textContent = val; output.textContent += arr1; console.clear(); val = JSON.stringify(obj1,rep); function rep(key,value){ console.log(key,value); if( typeof value === 'number'){ return undefined; } return value; } output.textContent = val; val = JSON.stringify(obj1,['num','first']); output.textContent = val; val = JSON.stringify(obj1,null); output.textContent = val; console.log(val); Course Source Code by Laurence Svekis https://basescripts.com/
• 12.
  val = JSON.stringify(obj1,null,''); output.textContent += val; console.log(val); const str1 = JSON.stringify(obj1,['num','first']); const str2 = JSON.stringify(arr1); console.clear(); console.log(str1); console.log(str2); const ob1 = JSON.parse(str1); const ob2 = JSON.parse(str2); console.clear(); console.log(ob1); console.log(ob2); JavaScript Stringify LocalStorage <!DOCTYPE html> <html> <head> <title>JavaScript Course</title> </head> <body> <input type="text"> <button>Check</button> <div class="output">Output</div> <script src="code6.js"></script> </body> </html> Course Source Code by Laurence Svekis https://basescripts.com/
• 13.
  const str1 ="Laurence Svekis"; const myObj = { first : "Laurence", last : "Svekis", id : 100 }; const myInput = document.querySelector('input'); const btn = document.querySelector('button'); const output = document.querySelector('.output'); document.addEventListener('DOMContentLoaded',init); btn.addEventListener('click',btnClicker); function btnClicker(){ const val = myInput.value; if(val.length > 0){ let user = JSON.parse(localStorage.getItem('user')); user.first = val; console.log(user); localStorage.setItem('user',JSON.stringify(user)); } } function init(){ console.log('ready'); output.innerHTML = ''; let val = localStorage.getItem('user'); let user = JSON.parse(val); if(!user.first){ let storeObj = JSON.stringify(myObj); localStorage.setItem('user',storeObj); Course Source Code by Laurence Svekis https://basescripts.com/
• 14.
  }else{ output.textContent = `${user.first}${user.last}`; } console.log(val); } JavaScript Every Method const arr1 = [1,4,54,23,5,7,34,66,1000]; const arr2 = ["Svekis","a","World","He"]; const arr3 = ["Svekis","Laurence","Cat","Hello","a","World"]; let val = arr1.every((ele)=>{ console.log(ele); return ele < 10; }) val = arr1.every(callBackFun); function callBackFun(ele,ind,arr){ console.log(`${ele} ${ind}`); return ele < 1000; } console.log(val); console.log(arr1.every(x => x < 10000)); console.log(arr1.every(x => x < 1000)); console.clear(); val = arr2.every((ele)=>{ console.log(ele); return ele.length < 15; Course Source Code by Laurence Svekis https://basescripts.com/
• 15.
  }) console.log(val); console.clear(); val = arr2.every((ele)=>{ console.log(ele); returnarr3.includes(ele); }) console.log(val); JavaScript Adding Numbers Array const arr1 = [32,43,556,2,3,4,4345]; let total = 0; for(let i=0;i<arr1.length;i++){ console.log(arr1[i],total); total += arr1[i]; } console.log(total); /* total = 0; for(let i in arr1){ console.log(arr1[i],total); total += arr1[i]; } console.log(total); */ total = 0; Course Source Code by Laurence Svekis https://basescripts.com/
• 16.
  for(let i=0,len=arr1.length;i<len;i++){ console.log(arr1[i],total); total +=arr1[i]; } console.log(total); Course Source Code by Laurence Svekis https://basescripts.com/