Can you reference a variable dynamically using JavaScript for Playwright

Question

I have a JSON file that I'm reading data from for a Playwright test as below:

async answerMyDetails(){
    const testDataFile = './myJsonFile.json'
    let data = await fs.readFile(testDataFile)
    let testData = await JSON.parse(data)

    await this.page.locator(`div:has(> label:has-text("Some Text")) input`).fill(`${testData.myDetailsPageQuestions.vehicleReg.answer_fullUkLicence_carInsurance}`)
}

I'd like to change this so that the _fullUkLicence_carInsurance part of the property that's being read from the JSON file is not hard coded and can be determined at the time the function is called, e.g. something like:

(answerSet == fullUkLicence_carInsurance)

async answerMyDetails(answerSet){
    const testDataFile = './myJsonFile.json'
    let data = await fs.readFile(testDataFile)
    let testData = await JSON.parse(data)

    await this.page.locator(`div:has(> label:has-text("Some Text")) input`).fill(`${testData.myDetailsPageQuestions.vehicleReg.answer_{answerSet}}`)
}

Answer 1

You can use bracket notation instead of dot notation to dynamically reference an object property name.

async answerMyDetails(answerSet){
    const testDataFile = './myJsonFile.json'
    let data = await fs.readFile(testDataFile)
    let testData = await JSON.parse(data)

    await this.page.locator(`div:has(> label:has-text("Some Text")) input`)
      .fill(testData.myDetailsPageQuestions.vehicleReg[`answer_${answerSet}`])
}