Fill cell value down until a new cell value occurs - Google Apps Script for Google Sheets

google_sheets_fill_values_down.js

// Google Apps Script to take a value in column A and fill it down until a new value shows up in a cell for Google Sheets
// Author: Al Chen ([email protected])
// Last Updated: September 6th, 2020
// Video tutorial: https://youtu.be/t-32QkyjKVE?t=106

function fillValuesDown() {
  var spreadsheet = SpreadsheetApp.getActive()
  var currentRange = spreadsheet.getRange("A2:A" + spreadsheet.getLastRow())
  var newRange = []
  var newFillValue
  currentRange.getValues().map(function(value) {
    if (value[0] !== '') {
      newFillValue = value[0]
      newRange.push([newFillValue])
    } else {
      newRange.push([newFillValue])
    }
  })
  currentRange.setValues(newRange)
}

How would this coding change if you wanted consistent text to be entered into any blank cell as the macro runs?

You could have to change up the if statement starting in row 12. You'll have to figure out a way to tell the script when to stop because it will just continue filling empty cells until the bottom of the sheet.