Javascript Question posted in
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javascript TypeError when referencing an array item

in javascript:

const weekdays = [‘mon’, ‘tue’,…

console.log(openingHours.mon); // works
console.log(weekdays[0]); // works, returns mon
console.log(openingHours.weekdays[0]); // fails with Uncaught TypeError: Cannot read properties of undefined (reading ‘0’)

why

tried console.log(openingHours.weekdays[0].toString());

failed also

Tags:

2

Answers


  1. Chosen as BEST ANSWER
    0

    weekdays[0] is not a property of openingHours so brackets must be used:

    console.log('fixed', openingHours[weekdays[0]]);

    rooky mistake, sorry if I wasted your time


  2. 0

    The way you are attempting to access the weekdays array inside the openingHours object is the problem. Mon is a property of openingHours, therefore using openingHours.mon works.

    However, weekdays is an array you’ve defined separately outside of openingHours and is not a property of openingHours.

    Instead of openingHours.weekdays[0] try openingHours[weekdays[0]]

    const weekdays = ['Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday'];

const openingHours = {
  'Monday': {
    open: "9:00 AM",
    close: "6:00 PM"
  },
  'Tuesday': {
    open: "9:00 AM",
    close: "6:00 PM"
  },
  'Wednesday': {
    open: "9:00 AM",
    close: "6:00 PM"
  },
  'Thursday': {
    open: "9:00 AM",
    close: "6:00 PM"
  },
  'Friday': {
    open: "9:00 AM",
    close: "9:00 PM"
  },
  'Saturday': {
    open: "10:00 AM",
    close: "5:00 PM"
  },
  'Sunday': {
    open: "Closed",
    close: "Closed"
  }
};

console.log(openingHours[weekdays[0]]);
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