(Javascript) My learning journey: String and more

const name = 'Mike Taylor' // direct character access console.log(name[0]) // M // Get position (zero base) console.log(name.indexOf('T')) // 5 // Modify one element name[0] = 'P' // Pike Taylor // Extract (slice) part or a string (start, stop before) console.log(name.slice(5)) // Taylor console.log(name.slice(5, 8)) // Tay console.log(name.slice(-2)) // or // Convert to lower or upper case console.log(name.toLowerCase()) // mike taylor console.log(name.toUpperCase()) // MIKE TAYLOR // Remove white space const title = ' This is a title with space ' console.log(title.trim()) // 'This is a title with space' // Chaining string method console.log(title.toLowerCase().trim()) // 'this is a title with space' // replace const name = 'Mike Taylor' console.log(name.replace('Mike', 'Paul') // Paul Taylor // includes? const name = 'Mike Taylor' console.log(name.includes('Mike')) // true // Split const colors = 'Red, Green, Blue') console.log(colors.split(',')) // ['Red', 'Green', 'Blue'] // Join const colors = ['Red', 'Green', 'Blue'] const colors_string = colors.join('-') // Red-Green-Blue 

// if first value truthy then return first value // if first value falsy then return second value  console.log('Hello' || 'Hi') // 'Hello' console.log('' || 'Bye') // 'Bye' console.log('' || 0 || 100) // 100 // Assignment example const maxUser = config.maxUser || 10 

// Only assign if null or undefined const maxUser = config.maxUser ?? 10 

if (customer.creditLimit) { if (customer.creditLimit.dateExpire) { console.log(customer.creditLimit.dateExpire) } } console.log(customer.creditLimit.dateExpire) // error // optional chaining: assign only if not undefined or null console.log(customer.creditLimit?.dateExpire) // undefined