References

Special characters

// Do
const units = 'μs';

// Don't
const units = '\\u03bcs'; // Greek letter mu, 's'

// Do
const output = '\\ufeff' + content;  // byte order mark

// Don't (no idea what this is)
const output = '\\ufeff' + content;

Modules

Avoid using default exports, as they allow inconsistent naming during import.

// Do
export class Foo {...}

// Or
class Foo {...}
export { Foo };

// Don't
export default class Foo {...}

Formatting

Empty blocks,

// Do
function doNothing() {}

// Don't
function doNothing() {
	// ...
}

Where to break line → a higher syntactic level,

// Do
const currentEstimate =
    calc(currentEstimate + x * currentEstimate) /
        2.0;

// Don't
const currentEstimate = calc(currentEstimate + x *
    currentEstimate) / 2.0;

Horizontal alignment: discouraged.

// Do
{
  tiny: 42, // this is great
  longer: 435, // this too
};

// Don't
{
  tiny:   42,  // permitted, but future edits
  longer: 435, // may leave it unaligned
};

JSDoc

Using markdown,

// Do
/**
 * Computes weight based on three factors:
 *
 *  - items sent
 *  - items received
 *  - last timestamp
 */