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VERSION 3

Used useRef hook to store mutable calculator data with objects as data structure.

The problem

  • It does not pass the fCC test suite.

VERSION 4

Will use the useState to store calculator data.

React state essentials: updating array

  1. Create a copy of the state's array. This will be used as an argument passed into the necessary functions to process.
  2. Or, create a callback within the setState function. [reference] (https://www.technetexperts.com/react-usestate-array-not-updating-a-common-problem-solved/)

Information

  • Arithmetic expression/equation (e.g., '3 + 5 x 6 - 2 / 4'), consists of:
    • numbers: positive and negative whole and/or decimal numbers,
    • operators: arithmetic operators and equals (x, /, +, -),
    • equality sign: =,
    • result value: a single value equal simplification of terms by arithmetic operation.

Data

  • Array for the arithmetic expression.
    • String elements, the numbers and operators.
  • Variable holds the result value.

State / prop

  • expression state for updating expression
  • display prop - contains the value of the expression state, for rendering display:
    • displays the inputted expression and the complete equation,
    • displays the latest component (number, operator, result) within the #display element.

Logic of functionality

  1. Capture mouse-input.
  2. Identify the applicable task:
    • Forman expression: numbers & operators.
    • Complete / simplify the expression, calculate the result: equals operator.
    • Clear / reset the calculator data.

Calculator tasks

  • Expression:
    1. Store input into the array.
    2. Inclusion / non-inclusion of the previous calculation result to start the expression.
      1. access the result in the expression array, expect valuse like 'Infinity' and 'NaN'.
      2. restart the expression array for a new expression.
    3. Validate for the correct sequence of expression.
    4. By condition(s), integrate a negative sign to numbers.
  • Calculation:
    1. Necessary correction to the expression before calculation.
    2. Calculate result using MDAS rule.
    3. Manage precision of result's decimal figures not less than four digits.
  • Clear: resets the expression state to its initial state.