when to use () and {} in arrow function i n js code example

Example 1: how to make javascript function consise

multiplyfunc = (a, b) => { return a * b; }

Example 2: concise body arrow functions javascript

const plantNeedsWater = day => day === 'Wednesday' ? true : false;

//If only 1 Parameter no () needed
//Single line return is implicit
//Single line no {} needed