Writing Elegant Frontend Code and Preparing for Technical Interviews

I have spent five years building backend management interfaces, mostly consisting of forms and tables, and reflect on how to improve the quality of such code for future interviews.

Write Elegant Code

Interview Question Example

During a Meituan interview I was asked to implement a size‑unit conversion function. My solution used a concise loop and template literals, which impressed the interviewer.

My implementation:

function formatSizeUnits(kb) {
  let units = ['KB', 'MB', 'GB', 'TB', 'PB'];
  let unitIndex = 0;
  while (kb >= 1024 && unitIndex < units.length - 1) {
    kb /= 1024;
    unitIndex++;
  }
  return `${kb.toFixed(2)} ${units[unitIndex]}`;
}

A colleague’s version used multiple if‑else branches and var declarations, achieving the same result but looking less modern.

function formatSizeUnits(kb) {
  var result = '';
  if (kb < 1024) {
    result = kb + ' KB';
  } else if (kb < 1024 * 1024) {
    result = (kb / 1024).toFixed(2) + ' MB';
  } else if (kb < 1024 * 1024 * 1024) {
    result = (kb / 1024 / 1024).toFixed(2) + ' GB';
  } else {
    result = (kb / 1024 / 1024 / 1024).toFixed(2) + ' TB';
  }
  return result;
}

Improving Code Quality

Code review is ideal, but many companies lack it; therefore, studying high‑quality open‑source code and leveraging AI tools like ChatGPT can help refactor and optimize implementations.

Example AI‑generated utility:

/**
 * Convert a file size from one unit to another.
 * @param {number} size - The numeric size.
 * @param {string} fromUnit - Original unit (e.g., 'KB').
 * @param {string} toUnit - Target unit (e.g., 'MB').
 * @param {number} [decimalPoint=2] - Decimal places.
 * @return {string} Formatted size with unit.
 */
function convertFileSize(size, fromUnit, toUnit, decimalPoint = 2) {
  const units = ['B','KB','MB','GB','TB','PB','EB','ZB','YB'];
  const fromIndex = units.indexOf(fromUnit);
  const toIndex = units.indexOf(toUnit);
  if (fromIndex === -1 || toIndex === -1) {
    throw new Error('Invalid units');
  }
  const exponent = toIndex - fromIndex;
  const resultSize = size / Math.pow(1024, exponent);
  return parseFloat(resultSize.toFixed(decimalPoint)) + ' ' + toUnit;
}

console.log(convertFileSize(1, 'GB', 'MB')); // 1024.00 MB

AI‑generated code should be reviewed before use.

Encapsulation

Repeated functionality should be packaged as reusable components, npm packages, or scaffolding tools to increase long‑term productivity and showcase deeper engineering skills.

Focus on Business

Understanding the domain is crucial for frontend developers; it differentiates you in interviews and helps you ask the right questions about requirements, data volume, pagination, and UI patterns.

Interview Scenario

A dialogue illustrates how lacking business knowledge can lead to interview failure.

How to Learn Business

When receiving a requirement, actively investigate its background and the meaning of displayed data (e.g., Kafka clusters, topics, brokers).

After delivery, follow up on usage metrics and efficiency gains.

Proactively suggest improvements such as pagination or virtual tables.

Read Source Code

Interviewers often probe knowledge of libraries like Vue, React, Axios, ECharts, husky, Vite, etc. Knowing the underlying mechanisms—e.g., Axios interceptors—allows you to discuss implementation details.

"Explain how Axios implements request/response interceptors."

Key points: Axios maintains an interceptor stack, each entry has `fulfilled` and `rejected` handlers, and they are composed into a promise chain before the final `then`/`catch`.

class InterceptorManager {
  constructor() { this.handlers = []; }
  use(fulfilled, rejected) { this.handlers.push({ fulfilled, rejected }); return this.handlers.length - 1; }
  eject(id) { if (this.handlers[id]) { this.handlers[id] = null; } }
  forEach(fn) { this.handlers.forEach(h => { if (h !== null) fn(h); }); }
}

During request/response processing, Axios iterates over these handlers to build the chain.

axios.interceptors.request.forEach(function unshiftRequestInterceptors(interceptor) {
  chain.unshift(interceptor.fulfilled, interceptor.rejected);
});
axios.interceptors.response.forEach(function pushResponseInterceptors(interceptor) {
  chain.push(interceptor.fulfilled, interceptor.rejected);
});

Frontend Infrastructure

Beyond business logic, developers should be familiar with tooling choices (Vue vs React, Vue2 vs Vue3, Element UI vs Ant Design, Vite vs Webpack), coding standards (ESLint, Stylelint, Prettier, Commitlint), monitoring (Sentry, window.onerror, PerformanceObserver), and CI/CD pipelines (Jenkins, GitLab CI, pipelines, stages, jobs).

Monitoring

Capture errors via `window.onerror` and `unhandledrejection`, map them with source maps, and report using `navigator.sendBeacon`, Fetch, or AJAX.

CI/CD

Configure pipelines to automatically build, test, and deploy on merge or push, understanding the roles of Pipeline, Stage, and Job.

Keeping Up with Technology

Stay aware of emerging trends such as low‑code platforms, AI assistants, WebAssembly, new bundlers (Vite, Bun), and even emerging ecosystems like HarmonyOS, as interviewers may ask about them.

Conclusion

Reflecting on past experiences, the author emphasizes that while perfect code is unattainable, continuous learning, business awareness, and leveraging modern tools can significantly improve interview outcomes and personal growth.