optimize removeLeadingZerosAndExplicitPlus function and fix name typo

Author: aditi-khare-mongoDB

src/int_32.ts

@@ -3,7 +3,7 @@ import { BSON_INT32_MAX, BSON_INT32_MIN } from './constants';
 import { BSONError } from './error';
 import type { EJSONOptions } from './extended_json';
 import { type InspectFn, defaultInspect } from './parser/utils';
-import { removeLeadingZerosandExplicitPlus } from './utils/string_utils';
+import { removeLeadingZerosAndExplicitPlus } from './utils/string_utils';
 
 /** @public */
 export interface Int32Extended {
@@ -49,7 +49,7 @@ export class Int32 extends BSONValue {
    * @param value - the string we want to represent as an int32.
    */
   static fromString(value: string): Int32 {
-    const cleanedValue = removeLeadingZerosandExplicitPlus(value);
+    const cleanedValue = removeLeadingZerosAndExplicitPlus(value);
 
     const coercedValue = Number(value);
 

src/long.ts

@@ -357,7 +357,7 @@ export class Long extends BSONValue {
     }
 
     // remove leading zeros (for later string comparison and to make math faster)
-    const cleanedStr = StringUtils.removeLeadingZerosandExplicitPlus(str);
+    const cleanedStr = StringUtils.removeLeadingZerosAndExplicitPlus(str);
 
     // check roundtrip result
     const result = Long._fromString(cleanedStr, unsigned, radix);

src/utils/string_utils.ts

@@ -2,12 +2,32 @@
  * @internal
  * Removes leading zeros and explicit plus from textual representation of a number.
  */
-export function removeLeadingZerosandExplicitPlus(str: string): string {
-  return !/[^+?0]+/.test(str)
-    ? str.replace(/^\+?0+/, '0') // all zeros case (remove explicit plus if it exists)
-    : str[0] === '-'
-      ? str.replace(/^-0+/, '-') // negative number with leading zeros
-      : str.replace(/^\+?0*/, ''); // remove explicit plus
+export function removeLeadingZerosAndExplicitPlus(str: string): string {
+  if (str === '') {
+    return str;
+  }
+
+  let startIndex = 0;
+
+  const isNegative = str[startIndex] === '-';
+  const isExplicitlyPositive = str[startIndex] === '+';
+
+  if (isExplicitlyPositive || isNegative) {
+    startIndex += 1;
+  }
+
+  let foundInsignificantZero = false;
+
+  while (str[startIndex] === '0') {
+    foundInsignificantZero = true;
+    startIndex += 1;
+  }
+
+  if (!foundInsignificantZero) {
+    return isExplicitlyPositive ? str.slice(1) : str;
+  }
+
+  return `${isNegative ? '-' : ''}${str.length === startIndex ? '0' : str.slice(startIndex)}`;
 }
 
 /**

test/node/utils/string_utils.test.ts

@@ -1,6 +1,7 @@
+import { expect } from 'chai';
 import * as StringUtils from '../../../src/utils/string_utils';
 
-describe('removeLeadingZerosandExplicitPlus()', function () {
+describe('removeLeadingZerosAndExplicitPlus()', function () {
   const inputs: [testName: string, str: string, expectedStr: string][] = [
     ['a string with zero with leading zeros', '000000', '0'],
     ['a string with positive leading zeros', '000000867', '867'],
@@ -14,7 +15,7 @@ describe('removeLeadingZerosandExplicitPlus()', function () {
   for (const [testName, str, expectedStr] of inputs) {
     context(`when the input is ${testName}`, () => {
       it(`should return a input string`, () => {
-        expect(StringUtils.removeLeadingZerosandExplicitPlus(str)).to.equal(expectedStr);
+        expect(StringUtils.removeLeadingZerosAndExplicitPlus(str)).to.equal(expectedStr);
       });
     });
   }