did problem solve in js

01-js/easy/anagram.js

@@ -5,7 +5,12 @@
 */
 
 function isAnagram(str1, str2) {
+  str1 = str1.replace(/\s/g, "").toLowerCase();
+  str2 = str2.replace(/\s/g, "").toLowerCase();
 
+  if(str1.length != str2.length) return false;
+
+  return str1.split("").sort().join("") === str1.split("").sort().join("");
 }
 
 module.exports = isAnagram;

01-js/easy/expenditure-analysis.js

@@ -14,7 +14,14 @@
 */
 
 function calculateTotalSpentByCategory(transactions) {
-  return [];
+  const categoryTotals = transactions.reduce((acc, tx) => {
+    acc[tx.category] = (acc[tx.category] || 0) + tx.price;
+    return acc;
+  }, {}); 
+  return Object.entries(categoryTotals).map(([category, totalSpent]) => ({
+    category,
+    totalSpent,
+  }));
 }
 
 module.exports = calculateTotalSpentByCategory;

01-js/easy/findLargestElement.js

@@ -6,7 +6,14 @@
 */
 
 function findLargestElement(numbers) {
-
+    let max = numbers[0];
+
+    for(let i = 0; i < numbers.length; i++) {
+        if(numbers[i] > max) {
+            max = numbers[i];
+        }
+    }
+    return max;
 }
 
 module.exports = findLargestElement;

01-js/hard/calculator.js

@@ -16,6 +16,68 @@
   Once you've implemented the logic, test your code by running
 */
 
-class Calculator {}
+class Calculator {
+  constructor() {
+    this.result = 0;
+  }
+
+  add(num) {
+    this.result += num;
+    return this.result;
+  }
+
+  subtract(num) {
+    this.result -= num;
+    return this.result;
+  }
+
+  multiply(num) {
+    this.result *= num;
+    return this.result;
+  }
+
+  divide(num) {
+    if(num === 0) {
+      throw new Error("Divide by zero is not allowed");
+    }
+
+    this.result /= num;
+    return this.result;
+  }
+
+  clear() {
+    this.result = 0;
+  }
+
+  getResult() {
+    return this.result;
+  }
+
+  calculate(expression) {
+    if(typeof expression !== "string") {
+      throw new Error("Expression must be string");
+    }
+
+    const sanitized = expression.replace(/\s/g, "");
+
+    if(/[^0-9+\-*().]/.test(sanitized)) {
+      throw new Error("Invalid characters in expression");
+    }
+
+    try {
+      const evalResult = new Function(`return ${sanitized}`)();
+
+      if(typeof evalResult !== "number" || isNaN(evalResult) || !isFinite(evalResult)) {
+        throw new Error("Invalid calculation");
+      }
+
+      this.result = evalResult;
+
+      return this.result;
+    } catch (err) {
+      throw new Error("Invalid expression");
+    }
+  }
+}
 
 module.exports = Calculator;

01-js/hard/todo-list.js

@@ -11,7 +11,38 @@
 */
 
 class Todo {
+  constructor() {
+    this.todos = [];
+  }
 
+  add(todo) {
+    this.todos.push(todo);
+  }
+  remove(index) {
+    if(index < 0 || index > this.todos.length) {
+      throw new Error("Invalid Index");
+    }
+    this.todos.splice(index);
+  }
+  update(index, updatedTdodo) {
+    if(index < 0 || index > this.todos.length) {
+      throw new Error("Invalid Index");
+    }
+    this.todos[index] = updatedTdodo;
+  }
+  get(index) {
+    if(index < 0 || index > this.todos.length) {
+      throw new Error("Invalid Index");
+    }
+    return this.todos[index];
+  }
+
+  getAll() {
+    return [...this.todos];
+  }
+  clear() {
+    this.todos = [];
+  }
 }
 
 module.exports = Todo;

01-js/medium/countVowels.js

@@ -6,7 +6,15 @@
 */
 
 function countVowels(str) {
-    // Your code here
+  const vowels = "aeiouAEIOU";
+  let count = 0;
+
+  for(let char of str) {
+    if(vowels.includes(char)) {
+      count++;
+    }
+  }
+  return count;
 }
 
 module.exports = countVowels;

01-js/medium/palindrome.js

@@ -4,7 +4,9 @@
 */
 
 function isPalindrome(str) {
-  return true;
+  const lowerStr = str.toLowerCase();
+  const reverseStr = lowerStr.split("").reverse().join("");
+  return lowerStr === reverseStr;
 }
 
 module.exports = isPalindrome;

01-js/medium/times.js

@@ -9,5 +9,16 @@ There is no automated test for this one, this is more for you to understand time
 */
 
 function calculateTime(n) {
-    return 0.01;
+    const startTime = new Date().getTime();
+
+    let sum = 0;
+    for(let i = 1; i<=n; i++) {
+        sum += i;
+    }
+
+    const endTime = new Date().getTime();
+
+    const timeInSec = (endTime - startTime) / 1000;
+
+    return timeInSec;
 }

week-2/01-async-js/easy/1-counter.md

@@ -1,4 +1,7 @@
 ## Create a counter in JavaScript
 
 We have already covered this in the second lesson, but as an easy recap try to code a counter in Javascript
-It should go up as time goes by in intervals of 1 second
+It should go up as time goes by in intervals of 1 second 
+
+
+DONE - pahari

week-2/01-async-js/easy/2-counter.md

@@ -4,6 +4,8 @@ Without using setInterval, try to code a counter in Javascript. There is a hint
 
 
 
+DONE - pahari;
+
 
 
 

week-2/01-async-js/easy/counter.js

@@ -0,0 +1,24 @@
+// function setCounter() {
+//     let count = 0;
+//     setInterval(() => {
+//         count++;
+//         console.log(count);
+//     }, 1000);
+// }
+
+// setCounter();
+
+
+
+function setCounter() {
+    let count = 0;
+    function tick() {
+        count++;
+        console.log(count);
+        setTimeout(tick, 1000);
+    }
+
+    tick();
+}
+
+setCounter();

week-2/01-async-js/easy/readfile.js

@@ -0,0 +1,28 @@
+const fs = require("fs");
+const path = require("path");
+
+console.log("start");
+
+const filepath = path.join(__dirname, "sample.txt");
+
+fs.readFile(filepath, "utf-8", (err, data) => {
+    if (err) {
+        console.error("Error reading file :", err);
+        return;
+    }
+    console.log("file data \n", data);
+})
+
+console.log("after start reading file");
+
+function expence(iter) {
+    let sum = 0;
+    for(let i = 0; i<iter; i++) {
+        sum += i;
+    }
+    console.log("operation done :", sum);
+}
+
+expence(1e8);
+
+console.log("end");

week-2/01-async-js/easy/sample.txt

@@ -0,0 +1 @@
+hii you are lazy

week-2/01-async-js/easy/writefile.js

@@ -0,0 +1,28 @@
+const fs = require("fs");
+const path = require("path");
+
+console.log("start");
+
+const filepath = path.join(__dirname, "sample.txt");
+
+fs.writeFile(filepath, "hii you are lazy", "utf-8", (err) => {
+    if(err) {
+        console.error("this is an error", err);
+    }
+
+    console.log("successfull write");
+})
+
+console.log("after start writing");
+
+function expense(iter) {
+    let sum = 0;
+    for(let i = 0; i < iter; i++) {
+        sum += i;
+    }
+    console.log(sum);
+}
+
+expense(1e9);
+
+console.log("end");

week-2/01-async-js/hard (promises)/1-promisify-setTimeout.js

@@ -3,6 +3,9 @@
 */
 
 function wait(n) {
+    return new Promise((resolve) => {
+        resolve();
+    }, n * 1000);
 }
 
 module.exports = wait;

week-2/01-async-js/hard (promises)/2-sleep-completely.js

@@ -5,6 +5,13 @@
  */
 
 function sleep(milliseconds) {
+    return new Promise((resolve) => {
+        const start = Date.now();
+        while (Date.now() - start < milliseconds) {
+
+        }
+        resolve();
+    })
 }
 
 module.exports = sleep;

week-2/01-async-js/hard (promises)/3-promise-all.js

@@ -5,19 +5,30 @@
  */
 
 function wait1(t) {
-
+    return new Promise((resolve) => {
+        setTimeout(resolve, t * 1000);
+    })
 }
 
 function wait2(t) {
-
+    return new Promise((resolve) => {
+        setTimeout(resolve, t * 1000);
+    })
 }
 
 function wait3(t) {
-
+    return new Promise((resolve) => {
+        setTimeout(resolve, t * 1000);
+    })
 }
 
 function calculateTime(t1, t2, t3) {
+    const start = Date.now();
+    return Promise.all([wait1(t1), wait2(t2), wait3(t3)]).then(() => {
+        const end = Date.now();
 
+        return end - start;
+    })
 }
 
 module.exports = calculateTime;