Do expressions

Baseline

Assign values based on a condition with better readability than ternaries.

Type	TC39	CoreJS	Babel	Civet	JS+
Syntax	✅ Stage 0 View		✅ View	✅ View	✅ via Babel

JS+ TypeScript

const x = 100;
const y = 20;

const a = do {
  if (x > 10) {
    if (y > 20) {
      'big x, big y';
    } else {
      'big x, small y';
    }
  } else {
    if (y > 10) {
      'small x, big y';
    } else {
      'small x, small y';
    }
  }
};

const x = 100;
const y = 20;

const a = x > 10
    ? y > 20
      ? 'big x, big y'
      : 'big x, small y'
    : y > 10
      ? 'small x, big y'
      : 'small x, small y';

Caution

Do expressions are different from Async do expressions

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Resources

• https://github.com/getify/You-Dont-Know-JS/blob/1st-ed/types%20%26%20grammar/ch5.md#statement-completion-values