How to delete existing text from input using Puppeteer?

You can use page.evaluate to manipulate DOM as you see fit:

await page.evaluate( () => document.getElementById("inputID").value = "")

However sometimes just manipulating a given field might not be enough (a target page could be an SPA with event listeners), so emulating real keypresses is preferable. The examples below are from the informative issue in puppeteer’s Github concerning this task.

Here we press Backspace as many times as there are characters in that field:

const inputValue = await page.$eval('#inputID', el => el.value);
// focus on the input field
await page.click('#inputID');
for (let i = 0; i < inputValue.length; i++) {
  await page.keyboard.press('Backspace');
}

Another interesting solution is to click the target field 3 times so that the browser would select all the text in it and then you could just type what you want:

const input = await page.$('#inputID');
await input.click({ clickCount: 3 })
await input.type("Blah");