Machine Coding Round: Code Quality Tips

Machine Coding Round: Code Quality Tips

Code quality is a key evaluation criterion. Clean, modular code scores higher than messy code. Here is how to write good code in the machine coding round.

1. Use Functions

Do not write one giant function. Break it into smaller functions:

// bad: one giant function
function buildAutocomplete() {
  // 200 lines of code
}

// good: small functions
function filterSuggestions(query, data) { ... }
function renderSuggestions(suggestions) { ... }
function handleInput(event) { ... }
function debounce(fn, delay) { ... }

2. Name Variables Clearly

// bad
const d = 300;
const a = [];
function f(e) { ... }

// good
const debounceDelay = 300;
const suggestions = [];
function handleInput(event) { ... }

3. Separate Concerns

• Data: managing the data source.
• Logic: filtering, sorting, transforming.
• UI: rendering, event handling.

// data
const data = ["apple", "banana", "cherry"];

// logic
function filterData(query) {
  return data.filter((item) => item.includes(query));
}

// UI
function renderResults(results) {
  resultsDiv.innerHTML = results.map((r) => `<li>${r}</li>`).join("");
}

4. Use Semantic HTML

<!-- bad -->
<div class="input"><input type="text" /></div>
<div class="list"><div class="item">apple</div></div>

<!-- good -->
<label for="search">Search</label>
<input type="text" id="search" />
<ul class="suggestions"><li>apple</li></ul>

5. Avoid Inline Styles

Use CSS classes instead of inline styles. It is cleaner and more maintainable.

<!-- bad -->
<div style="padding: 10px; border: 1px solid #ccc;"></div>

<!-- good -->
<div class="card"></div>

6. Remove Console Logs

Before submitting, remove console.log statements. They make the code look unfinished.

7. Handle Errors Gracefully

try {
  const data = await fetchData();
  render(data);
} catch (err) {
  renderError("Failed to load data");
}

8. Comment Complex Logic

Only comment complex or non-obvious logic. Do not comment every line.

// debounce: delay the call until activity stops
function debounce(fn, delay) { ... }

The Takeaway

Write clean code: use small functions, name variables clearly, separate concerns (data, logic, UI), use semantic HTML, avoid inline styles, remove console logs, handle errors, and comment complex logic. Clean code scores higher than messy code.