arrays.js

// bracket pair colorizer
const arrayOfNames = ["martin", "scott", "craig", "maya"];

arrayOfNames.forEach(function(names) {
  console.log(names)
})

for (let name of arrayOfNames) {
  console.log(name);
}

for (let [index,name] of arrayOfNames.entries()) {
  console.log(`${index:} ${name}`);
}

for (let nameIndex in arrayOfNames) {
  console.log(arrayOfNames[nameIndex])
}

arrayOfNames.forEach(name => console.log(name));  

const arrayOfNumbers = [1, 10, 12, 14];

function sumNumbers(numbersArray) {
  let total = 0;

  for (let number of numbersArray) {
    total += number;
  }

  console.log(total);
}

sumNumbers(arrayOfNumbers)

iterating-over-people.js

const person = {
  firstName: "Martin",
  lastName: "Laws",
  heightInCm: 188
};

const objectKeys = Object.keys(person);

// this is a _for of_ loop:
for (let key of objectKeys) {
  console.log(`${key}: ${person[key]}`);
}

const objectValues = Object.values(person);

// this is a _for in_ loop, it returns index position for each item in the array:
for (let indexPosition in objectKeys) {
  console.log(`${objectKeys[indexPosition]}: ${objectValues[indexPosition]}`);
}

// this is uses Object.entries() which returns an array of [key, value] for each key/value pair in an object:
console.log(Object.entries(person));

person.js

const person = {
  firstName: 'Martin',
  lastName: 'Laws',
  fullName: function() {
    return `${this.firstName} ${this.lastName}`;
  },
  heightInCm: 188,
  heightInInches() {
    return this.heightInCm * 2.54
  }
}

console.log(person.firstName)
console.log(person.lastName)
console.log(person.heightInCm)
console.log(person.fullName())