Work still in progress

assets/js/numbers.js

@@ -1,3 +1,88 @@
 function compute(expression) {
-    // TODO - write method definition here
-}
+
+    let operators = new Array();
+    for (let i = 0; i < expression.split(/[^\D]/).length; i++) {
+        if (expression.split(/[^\D]/)[i] != "") operators.push(expression.split(/[^\D]/)[i]);
+    }
+
+    let numbers = expression.split(/\D/);
+    for (let i = 0; i < numbers.length; i++) {
+        numbers[i] = parseInt(numbers[i]);
+    }
+
+    let jsonOp = jsonOfOperators(operators);
+    let arrayOfUsedoperands = new Array();
+    let result = null;
+
+    result = calcOnOperator( "*", result, numbers, operators, arrayOfUsedoperands, jsonOp.multiplication);
+    result = calcOnOperator("/", result, numbers, operators, arrayOfUsedoperands, jsonOp.division);
+    result = calcOnOperator("-", result, numbers, operators, arrayOfUsedoperands, jsonOp.subtraction);
+
+    return calcOnOperator("+",result, numbers, operators, arrayOfUsedoperands, jsonOp.addition);
+}
+
+// Operate the calculation base on the operator
+function calculation(operator, operand1, operand2) {
+    switch (operator) {
+        case "+":
+            return operand1 + operand2;
+        case "-":
+            return operand1 - operand2;
+        case "*":
+            return operand1 * operand2;
+        case "/":
+            return operand1 / operand2;
+    }
+}
+
+// Return a JSON object of each operator and its occurence, will be use to determine the order of operation
+let jsonOfOperators = (arrayOfOperators) => {
+    return {
+        multiplication: arrayOfOperators.filter(element => element == "*").length,
+        division: arrayOfOperators.filter(element => element == "/").length,
+        addition: arrayOfOperators.filter(element => element == "+").length,
+        subtraction: arrayOfOperators.filter(element => element == "-").length
+    };
+}
+
+// Check the current operator position from the calculation already done, and update the result array
+let checkUpdateResult = (result, numbers, operators, arrayOfUsedoperands, operator) => {
+
+    // Check the current operation base on the last result
+    if (result == numbers[operators.indexOf(operator)] || result == numbers[operators.indexOf(operator) + 1]) {
+        // When the current operation does affect the previous operation, update all the element already used in a calculation to the current result
+        // Also update the array of the index of operands already used
+        result = calculation(operator, numbers[operators.indexOf(operator)], numbers[operators.indexOf(operator) + 1]);
+        arrayOfUsedoperands.push(operators.indexOf(operator));
+        arrayOfUsedoperands.push(operators.indexOf(operator) + 1);
+        for (let j = 0; j < arrayOfUsedoperands.length; j++) {
+            numbers[arrayOfUsedoperands[j]] = result;
+        }
+    } else {
+        // When the current operation does not affect the previous operation result, do not update all the element already used in a calculation to the current result
+        result = calculation(operator, numbers[operators.indexOf(operator)], numbers[operators.indexOf(operator) + 1]);
+        numbers[operators.indexOf(operator)] = result;
+        numbers[operators.indexOf(operator) + 1] = result;
+    }
+    // Delete the current operator to evoid using it twice
+    operators[operators.indexOf(operator)] = "";
+}
+
+let calcOnOperator = (operator, result, numbers, operators, arrayOfUsedoperands, numberOfOccurence) => {
+    if (numberOfOccurence != 0) {
+        if (result == null) result = numbers[operators.indexOf(operator)];
+        for (let i = 0; i < numberOfOccurence; i++) {
+            checkUpdateResult(result, numbers, operators, arrayOfUsedoperands, operator);
+
+            // Debugger
+            // console.log("++++++++++++++++");
+            // console.log(i + " " + operator + " iteration array of used indexes " + arrayOfUsedoperands);
+            // console.log(i + " " + operator + " iteration operators = " + operators);
+            // console.log(i + " " + operator + " iteration numbers = " + numbers);
+            // console.log("++++++++++++++++");
+        }
+    }
+    return numbers[arrayOfUsedoperands[arrayOfUsedoperands.length - 1]];
+}
+
+