javascript promise wait for function to finish code example

Example 1: javascript synchronous wait

function delay(n) {  
  n = n || 2000;
  return new Promise(done => {
    setTimeout(() => {
      done();
    }, n);
  });
}

Example 2: wait for ajax to finish

function functABC() {
  return new Promise(function(resolve, reject) {
    $.ajax({
      url: 'myPage.php',
      data: {id: id},
      success: function(data) {
        resolve(data) // Resolve promise and go to then()
      },
      error: function(err) {
        reject(err) // Reject the promise and go to catch()
      }
    });
  });
}

functABC().then(function(data) {
  // Run this when your request was successful
  console.log(data)
}).catch(function(err) {
  // Run this when promise was rejected via reject()
  console.log(err)
})

Example 3: how to wait for a function to finish in javascript

function doFirst() {
  return new Promise(function(resolve, reject) {
    //do a thing
      if (){
          return reject(value);
  	  }
      resolve(value);
    });
  });
}

async function doSecond() {
    var outputValue = await doFirst();
    console.log(outputValue);
}