1. Merging Duplicate Array Elements

---

// Merge elements with duplicate prcdTermType and acctFnm properties
mergeDuplicates(arr) {
 const result = [];
 const lookup = {};

 arr.forEach(item => {
   const key = `${item.prcdTermType}-${item.acctFnm}`;
   if (lookup[key]) {
     lookup[key].pymtPrice = Number(lookup[key].pymtPrice) + Number(item.pymtPrice);
   } else {
     lookup[key] = { ...item };
     result.push(lookup[key]);
   }
 });

 return result;
},

2. Calculating Sum of Specific Array Properties

---

// Calculate total of specified property in array
calculateSum(arr, propName) {
 return arr.reduce((sum, item) => {
   return item[propName] ? sum + Number(item[propName]) : sum;
 }, 0);
},

3. Enum Value Transformation

---

// Project category enum
projectCategories: [
 { value: '1', label: 'Deposit' },
 { value: '2', label: 'Down Payment' },
 { value: '3', label: 'Registration' },
 { value: '4', label: 'Mortgage' },
 { value: '5', label: 'Full Payment' },
 { value: '6', label: 'Initial Payment' },
 { value: '7', label: 'Pre-interest' },
 { value: '8', label: 'Consultation Fee' },
 { value: '9', label: 'GPS' },
 { value: '10', label: 'Accessories' },
 { value: '11', label: 'Sticky Products' },
 { value: '12', label: 'Minor Items' },
 { value: '13', label: 'Other Projects' },
 { value: '14', label: 'Registration Deposit' },
 { value: '15', label: 'Trade-in Deposit' },
 { value: '16', label: 'GD Receivables' },
 { value: '17', label: 'GD Income' },
 { value: '18', label: 'High Margin Amount' },
 { value: '19', label: 'Other Deposits' },
],

transformProjectValues(valueString) {
 if (!valueString) return '';
 return valueString.split(',').map(code => {
   const found = this.projectCategories.find(cat => cat.value === code);
   return found ? found.label : code;
 }).join(',');
},

4. Sorting Arrays by Property Values

---

// Sort array based on specific property
sortPayments(array, sortProperty) {
 const priorityOrder = ['5', '6'];
 
 return array.sort((a, b) => {
   const aPriority = priorityOrder.indexOf(a[sortProperty]);
   const bPriority = priorityOrder.indexOf(b[sortProperty]);
   
   if (aPriority !== -1 && bPriority === -1) return -1;
   if (aPriority === -1 && bPriority !== -1) return 1;
   return 0;
 });
},

5. Calculating Price Differences Between Arrays

---

// Calculate price differences between two arrays
calculateDifferences(sourceArray, targetArray) {
 return sourceArray.map(item => {
   const matchingItems = targetArray.filter(target => target.prcdPrj === item.prcdPrj);
   const total = matchingItems.reduce((sum, curr) => 
     sum + Number(curr.pymtPrice) + Number(curr.depositAmount) + Number(curr.zhDeduction), 0);
   
   return {
     prcdPrj: item.prcdPrj,
     id: item.id,
     name: item.name,
     difference: item.prcdPrice - total
   };
 });
},

6. Form Validation Focus Management

---

export function focusValidationError() {
 const errorFields = document.querySelectorAll('.van-field--error');
 if (errorFields.length > 0) {
   const firstError = errorFields[0].querySelector('.van-field__control');
   if (firstError) {
     firstError.focus();
   }
 }
}

7. File Download Utility

---

// Download file utility function
export function downloadData(content, filename, extension) {
 const blob = new Blob([content]);
 const url = URL.createObjectURL(blob);
 const link = document.createElement('a');
 
 link.href = url;
 link.download = `${new Date().toISOString().slice(0, 10)}-${filename}.${extension}`;
 document.body.appendChild(link);
 link.click();
 document.body.removeChild(link);
 URL.revokeObjectURL(url);
}

8. Conditional CSS Class Management

---

/**
* Check if element has specific class
*/
export function hasClass(element, className) {
 return element.classList.contains(className);
}

/**
* Add class to element
*/
export function addClass(element, className) {
 if (!hasClass(element, className)) {
   element.classList.add(className);
 }
}

// Usage example
const targetElement = document.getElementById('target-div');
addClass(targetElement, 'highlighted');

9. Generating Random String Identifiers

---

/**
* Generate unique 32-bit string identifier
*/
export function generateUniqueId() {
 const timestamp = Date.now().toString();
 const random = Math.floor(Math.random() * 65536).toString();
 return (parseInt(random + timestamp)).toString(32);
}

10. Removing Duplicates from Object Arrays

---

/**
* Remove duplicates from array of objects
*/
export function removeDuplicates(array) {
 return array.filter((item, index, self) => 
   index === self.findIndex(obj => JSON.stringify(obj) === JSON.stringify(item))
 );
}

11. Debounce Function Implementation

---

/**
* Debounce function execution
*/
export function createDebounce(func, delay, immediate = false) {
 let timeoutId;
 
 return function(...args) {
   const callNow = immediate && !timeoutId;
   
   clearTimeout(timeoutId);
   timeoutId = setTimeout(() => {
     timeoutId = null;
     if (!immediate) func.apply(this, args);
   }, delay);
   
   if (callNow) func.apply(this, args);
 };
}

12. Toggle CSS Classes

---

/**
* Toggle CSS class on element
*/
export function toggleClass(element, className) {
 if (!element || !className) return;
 
 if (element.classList.contains(className)) {
   element.classList.remove(className);
 } else {
   element.classList.add(className);
 }
}

13. Extract Text Content from HTML

---

/**
* Convert HTML to plain text
*/
export function extractText(htmlString) {
 const tempDiv = document.createElement('div');
 tempDiv.innerHTML = htmlString;
 return tempDiv.textContent || tempDiv.innerText || '';
}

// Usage
const htmlContent = '<p>Hello <strong>World!</strong></p>';
const plainText = extractText(htmlContent);
console.log(plainText); // Outputs: "Hello World!"

14. Parse URL Query Parameters

---

/**
* Convert URL query string to object
*/
export function parseQueryString(url) {
 const queryString = url.split('?')[1];
 if (!queryString) return {};
 
 const params = {};
 queryString.split('&').forEach(pair => {
   const [key, value] = pair.split('=');
   params[decodeURIComponent(key)] = decodeURIComponent(value || '');
 });
 
 return params;
}

// Usage
const url = 'http://example.com/?name=John&age=30';
const queryParams = parseQueryString(url);
console.log(queryParams); // { name: "John", age: "30" }

15. Convert Object to URL Parameters

---

/**
* Convert object to URL parameter string
*/
export function objectToParams(obj) {
 return Object.entries(obj)
   .filter(([_, value]) => value !== undefined)
   .map(([key, value]) => 
     `${encodeURIComponent(key)}=${encodeURIComponent(value)}`
   )
   .join('&');
}

// Usage
const data = {
 name: 'John Doe',
 age: 30,
 city: undefined,
 job: 'Developer'
};

const params = objectToParams(data);
console.log(params); // name=John%20Doe&age=30&job=Developer

16. Extract Query Parameters from URL

---

/**
* Extract query parameters from URL
*/
export function getQueryParams(url = window.location.href) {
 const params = {};
 const queryString = url.split('?')[1];
 
 if (queryString) {
   queryString.split('&').forEach(pair => {
     const [key, value] = pair.split('=');
     params[decodeURIComponent(key)] = decodeURIComponent(value || '');
   });
 }
 
 return params;
}

// Usage
const url = 'http://example.com/?name=John&age=30';
const query = getQueryParams(url);
console.log(query); // { name: 'John', age: '30' }

17. Calculate Date Difference

---

/** 
* Calculate difference between two dates in days
*/
export function calculateDateDifference(startDate, endDate) {
 if (!startDate || !endDate) return 0;
 const diffTime = Math.abs(endDate - startDate);
 return Math.ceil(diffTime / (1000 * 60 * 60 * 24));
}

18. Convert Date Format to Timestamp

---

/**
* Convert date string to timestamp
*/
export function dateStringToTimestamp(dateString) {
 if (!dateString) return null;
 
 let formattedDate = dateString;
 if (dateString.length === 19) {
   formattedDate = dateString.replace(/-/g, '/');
 } else {
   formattedDate = (dateString + ':00').replace(/-/g, '/');
 }
 
 return new Date(formattedDate).getTime();
}

19. Component Form Validation Helper

---

// Form validation utility
export function validateForm(componentRef, callback) {
 componentRef.validate(isValid => {
   callback(isValid);
 });
}

// Example usage in Vue component
export default {
 methods: {
   submitForm() {
     validateForm(this.$refs.formComponent, (isValid) => {
       if (isValid) {
         console.log('Form valid, proceeding with submission');
       } else {
         console.error('Form validation failed');
       }
     });
   }
 }
}

20. Currency Input Validation

---

// Validate currency input (positive numbers only)
export function validateCurrency(rule, value, callback) {
 const regex = /(?:^[1-9]([0-9]+)?(?:\.[0-9]{1,2})?$)|(?:^(?:0)$)|(?:^[0-9]\.[0-9](?:[0-9])?$)/;
 
 if (value === '' || value === undefined || value === null) {
   callback();
 } else if (!regex.test(value)) {
   callback(new Error('Please enter a valid number'));
 } else {
   callback();
 }
}

21. Positive Number Validation

---

// Validate positive numbers including decimals
export function validatePositiveNumber(rule, value, callback) {
 const regex = /^[+][1-9](\d+)$|^[+]{0,1}(\d+\.\d+)$/;
 
 if (value === '' || value === undefined || value === null) {
   callback();
 } else if (!regex.test(value)) {
   callback(new Error('Please enter a valid positive number'));
 } else {
   callback();
 }
}

22. Phone Number Validation

---

// Validate phone numbers and landlines
export function validatePhoneNumber(rule, value, callback) {
 const mobilePattern = /^(([1][3,4,5,7,8]\d{9})|([0]\d{10,11})|(\d{7,8})|(\d{4}|\d{3})-(\d{7,8}))$/;
 const landlinePattern = /^\d{3}-\d{8}|\d{4}-\d{7}$/;

 if (!value || value === '') {
   callback(new Error('Please enter a contact method'));
 } else if (value.length === 11) {
   if (value.indexOf('-') !== -1) {
     callback();
   } else if (mobilePattern.test(value)) {
     callback();
   } else {
     callback(new Error('Please enter a valid phone number or landline (format: area-code-number)'));
   }
 } else if (value.length === 12) {
   if (landlinePattern.test(value)) {
     callback();
   } else {
     callback(new Error('Please enter a valid phone number or landline (format: area-code-number)'));
   }
 } else {
   callback(new Error('Please enter a valid phone number or landline (format: area-code-number)'));
 }
}

23. Alphanumeric with Uppercase Requirement

---

// Validate alphanumeric with uppercase requirement
export function validateAlphanumericWithUpper(rule, value, callback) {
 const regex = /^(?=.*[A-Z])(?=.*\d)[a-zA-Z\d]+$/;
 
 if (value === '' || value === undefined || value === null) {
   callback();
 } else if (!regex.test(value)) {
   callback(new Error('Must contain letters, numbers, and at least one uppercase letter'));
 } else {
   callback();
 }
}

24. Concurrent API Requests

---

async fetchAccountData() {
 try {
   const [cpResponse, szResponse] = await Promise.all([
     api.getAccountDetails({ cpAcctId: this.formData.cpAcctId }),
     api.getAccountDetails({ szAcctId: this.formData.szAcctId })
   ]);
   
   console.log('CP Account:', cpResponse);
   console.log('SZ Account:', szResponse);
   
 } catch (error) {
   console.error('Failed to fetch account data:', error);
 }
},

25. Default Value for Cascader Component

---

<el-cascader
 v-model="formData.vehicleBrand"
 :options="brandOptions"
 filterable
 :props="cascaderProps"
 clearable
/>

// Initialize default selection
computed: {
 cascaderProps() {
   return {
     label: 'name',
     value: 'name',
     children: 'children',
     expandTrigger: 'hover',
     checkStrictly: true
   };
 }
},
methods: {
 getDefaultPath(options) {
   if (!options || options.length === 0) return [];
   
   const firstOption = options[0];
   if (firstOption.children && firstOption.children.length > 0) {
     return [firstOption.name, ...this.getDefaultPath(firstOption.children)];
   }
   return [firstOption.name];
 }
}

// Set initial value
this.formData.vehicleBrand = this.getDefaultPath(this.brandOptions);

26. Checking Uniformity of Array Properties

---

// Check if all items have same property value
function checkPropertyConsistency(array, propertyName) {
 if (array.length === 0) return true;
 
 const firstValue = array[0][propertyName];
 return array.every(item => item[propertyName] === firstValue);
}

27. VIN Number Validation

---

// Validate VIN number according to GB standard
function validateVin(vin) {
 const vinRegex = /^[A-HJ-NPR-Z0-9]{17}$/;
 if (!vinRegex.test(vin)) return false;

 const weights = [8, 7, 6, 5, 4, 3, 2, 10, 0, 9, 8, 7, 6, 5, 4, 3, 2];
 const values = {
   0: 0, 1: 1, 2: 2, 3: 3, 4: 4, 5: 5, 6: 6, 7: 7, 8: 8, 9: 9,
   A: 1, B: 2, C: 3, D: 4, E: 5, F: 6, G: 7, H: 8,
   J: 1, K: 2, L: 3, M: 4, N: 5, P: 7, R: 9,
   S: 2, T: 3, U: 4, V: 5, W: 6, X: 7, Y: 8, Z: 9
 };

 let sum = 0;
 for (let i = 0; i < 17; i++) {
   const char = vin[i].toUpperCase();
   sum += values[char] * weights[i];
 }

 const checkDigit = sum % 11 === 10 ? 'X' : (sum % 11).toString();
 return vin[8].toUpperCase() === checkDigit;
}

28. Advacned Debounce Implementation

---

export function debounce(func, wait, immediate = false) {
 let timeoutId;
 
 return function(...args) {
   const callNow = immediate && !timeoutId;
   
   clearTimeout(timeoutId);
   timeoutId = setTimeout(() => {
     timeoutId = null;
     if (!immediate) func.apply(this, args);
   }, wait);
   
   if (callNow) func.apply(this, args);
 };
}

// Usage example
const debouncedSearch = debounce((query) => {
 performSearch(query);
}, 300);

// Call multiple times rapidly, only executes once after 300ms
debouncedSearch('term1');
debouncedSearch('term2');
debouncedSearch('term3');

29. Date Utilities

---

• Get current date in YYYY-MM-DD format

getCurrentDate() {
 const now = new Date();
 const year = now.getFullYear();
 const month = String(now.getMonth() + 1).padStart(2, '0');
 const day = String(now.getDate()).padStart(2, '0');
 return `${year}-${month}-${day}`;
},

// Convert time string to minutes
convertTimeToMinutes(timeString) {
 const [hours, minutes] = timeString.split(':').map(Number);
 return hours * 60 + minutes;
},

30. Date Picker Restrictions

---

// Disable past dates
disabledPastDates(date) {
 return date.getTime() < Date.now() - 8.64e7;
}

// Restrict date range to today plus 30 days
restrictedDateRange(date) {
 const today = new Date();
 const maxDate = new Date(today.getFullYear(), today.getMonth(), today.getDate() + 30);
 return date.getTime() < today.getTime() || date.getTime() > maxDate.getTime();
}

31. Table Selection Control

---

// Disable selection based on condition
disableSelection(row) {
 return row.quantity === 0;
}

// Process array to set selectable flags
processSelectionStatus(items) {
 return items.map(item => ({
   ...item,
   selectable: item.quantity > 0
 }));
}

32. Paramter Serialization

---

// Serialize object to query parameters
const params = {
 method: 'get',
 id: 1,
 name: 'yjn'
};

const serialized = new URLSearchParams(params).toString();
// Result: "method=get&id=1&name=yjn"

// Serialize array
const arrayParam = [2, 3];
const serializedArray = new URLSearchParams({ arr: arrayParam }).toString();
// Result: "arr=2&arr=3"

// With custom serialization
const customSerialized = new URLSearchParams({ 
 arr: arrayParam 
}).toString({ indices: false });
// Result: "arr=2&arr=3"

33. Table Summary Calculation

---

// Basic summary calculation
calculateTableSummary(columns) {
 const numericColumns = ['amt', 'costAmt', 'qty', 'recAmt'];
 
 return columns.map((column, index) => {
   if (index === 0) return 'Total';
   
   const columnName = column.property.includes('.') 
     ? column.property.split('.')[1] 
     : column.property;
     
   if (numericColumns.includes(columnName)) {
     return this.calculateSum(this.tableData, columnName);
   }
   return '';
 });
},

34. Form Layout Behavior

---

• When :inline="false" - form fields adapt to container width
• When :inline="true" - form fields maintain fixed widths

35. Avoiding Boolean Conversion of Zero

---

• Solution 1: Explicit zero comparison

if (myValue === 0 || myValue) {
 // Handle both zero and truthy values
}

• Solution 2: Complex boolean logic

if (!(myValue === 0 ? false : !myValue)) {
 // Handles zero correctly
}

36. Numeric Value Validation

---

// Check if value is a number and not falsy except zero
if (!isNaN(myValue) && !(myValue === 0 ? false : !myValue)) {
 // Valid numeric value
}

// Alternative ternary approach
v-if="myValue === 0 ? true : !!myValue"