svelte/compiler/validate/js/index.js

import propValidators from './propValidators/index.js';
import FuzzySet from './utils/FuzzySet.js';
import checkForDupes from './utils/checkForDupes.js';
import checkForComputedKeys from './utils/checkForComputedKeys.js';

const validPropList = Object.keys( propValidators );

const fuzzySet = new FuzzySet( validPropList );

export default function validateJs ( validator, js ) {
	js.content.body.forEach( node => {
		// check there are no named exports
		if ( node.type === 'ExportNamedDeclaration' ) {
			validator.error( `A component can only have a default export`, node.start );
		}

		if ( node.type === 'ExportDefaultDeclaration' ) {
			if ( validator.defaultExport ) {
				validator.error( `Duplicate default export`, node.start );
			}

			validator.defaultExport = node;
		}
	});

	// ensure all exported props are valid
	if ( validator.defaultExport ) {
		checkForComputedKeys( validator, validator.defaultExport.declaration.properties );
		checkForDupes( validator, validator.defaultExport.declaration.properties );

		validator.defaultExport.declaration.properties.forEach( prop => {
			validator.templateProperties[ prop.key.value ] = prop;
		});

		validator.defaultExport.declaration.properties.forEach( prop => {
			const propValidator = propValidators[ prop.key.name ];

			if ( propValidator ) {
				propValidator( validator, prop );
			} else {
				const matches = fuzzySet.get( prop.key.name );
				if ( matches && matches[0] && matches[0][0] > 0.7 ) {
					validator.error( `Unexpected property '${prop.key.name}' (did you mean '${matches[0][1]}'?)`, prop.start );
				} else if ( /FunctionExpression/.test( prop.value.type ) ) {
					validator.error( `Unexpected property '${prop.key.name}' (did you mean to include it in 'methods'?)`, prop.start );
				} else {
					validator.error( `Unexpected property '${prop.key.name}'`, prop.start );
				}
			}
		});
	}
}