ts-cast/esm/types/union.js

Runtime typechecking

import { casterApi } from '../engine';
import { throwTypeError } from '../engine/throw-type-error';
import { withName } from '../helpers/names';
const checkTypes = (casters, typeName) => {
    const unionCasterFn = (value, context, reportError = throwTypeError) => {
        let match;
        const errors = [];
        const isMatched = casters.some(caster => {
            try {
                match = caster(value, context);
                return true;
            }
            catch (err) {
                errors.push(`${caster.name}: ${err.message}`);
                return false;
            }
        });
        if (isMatched)
            return match;
        return reportError(`${typeName} is expected${context ? ` in ${context}` : ''} but no matching type was found:\n${errors.map(e => `  - ${e}`).join('\n')}`, context);
    };
    return unionCasterFn;
};
export const union = (...casters) => {
    if (casters.length < 2) {
        throw new Error('At least two types should be specified.');
    }
    const typeName = casters.map(c => c.name).join('|');
    const casterFn = checkTypes(casters, typeName);
    return casterApi(withName(casterFn, typeName));
};
export const firstOf = union;
export const oneOf = union;