UnaryExpression.js
1002 Bytes
/**
* Extractor function for a UnaryExpression type value node.
* A unary expression is an expression with a unary operator.
* For example, !"foobar" will evaluate to false, so this will return false.
*
* @param - value - AST Value object with type `UnaryExpression`
* @returns - The extracted value converted to correct type.
*/
export default function extractValueFromUnaryExpression(value) {
// eslint-disable-next-line global-require
const getValue = require('./index.js').default;
const { operator, argument } = value;
switch (operator) {
case '-':
return -getValue(argument);
case '+':
return +getValue(argument); // eslint-disable-line no-implicit-coercion
case '!':
return !getValue(argument);
case '~':
return ~getValue(argument); // eslint-disable-line no-bitwise
case 'delete':
// I believe delete statements evaluate to true.
return true;
case 'typeof':
case 'void':
default:
return undefined;
}
}