Create string_to_integer.js

Author: Jaskaran Singh

string_to_integer.js

@@ -0,0 +1,53 @@
+/**
+ * @param {string} str
+ * @return {number}
+ */
+
+let isNegative;
+var myAtoi = function(str) {
+    isNegative = 0;
+    str = str.trim();
+    
+    if(str[0] === "-" || str[0] === "+" || !isNaN(str[0])) {
+        if(str[0] === "+") {
+            return checkNumber(str, 1);   
+        } else if(!isNaN(str[0])) {
+            return checkNumber(str, 0);
+        } else {
+            if(str[0] === "-") {
+                isNegative = 1;
+                str = str.substring(1, str.length);
+                
+                return checkNumber(str, 0);
+            }
+        }
+    } else {
+        return 0;
+    }
+};
+
+let checkNumber = (currentString, currentIndex) => {
+    let newNumber = "";
+    let INT_MIN = Math.pow(-2, 31);
+    let INT_MAX = Math.pow(2, 31) - 1;
+    
+    for(let i = 0; i < currentString.length; currentIndex++, i++) {
+        if(isNaN(currentString.charAt(currentIndex)))
+            break;
+        
+        if(currentString.charAt(currentIndex) === " ")
+            break;
+        
+        newNumber += currentString.charAt(currentIndex);
+    }
+    
+    if(isNegative)
+        newNumber *= -1;
+    
+    if(newNumber < INT_MIN)
+        return INT_MIN;
+    else if(newNumber > INT_MAX)
+        return INT_MAX;
+    
+    return newNumber;
+}