openapi-typescript-codegen/src/utils/registerHandlebarHelpers.ts

import Handlebars from 'handlebars';

import { Enum } from '../client/interfaces/Enum';
import { Model } from '../client/interfaces/Model';
import { HttpClient } from '../HttpClient';
import { unique } from './unique';

export function registerHandlebarHelpers(root: {
    httpClient: HttpClient;
    useOptions: boolean;
    useUnionTypes: boolean;
}): void {
    Handlebars.registerHelper(
        'equals',
        function (this: any, a: string, b: string, options: Handlebars.HelperOptions): string {
            return a === b ? options.fn(this) : options.inverse(this);
        }
    );

    Handlebars.registerHelper(
        'notEquals',
        function (this: any, a: string, b: string, options: Handlebars.HelperOptions): string {
            return a !== b ? options.fn(this) : options.inverse(this);
        }
    );

    Handlebars.registerHelper(
        'containsSpaces',
        function (this: any, value: string, options: Handlebars.HelperOptions): string {
            return /\s+/.test(value) ? options.fn(this) : options.inverse(this);
        }
    );

    Handlebars.registerHelper(
        'union',
        function (this: any, properties: Model[], parent: string | undefined, options: Handlebars.HelperOptions) {
            const type = Handlebars.partials['type'];
            const types = properties.map(property => type({ ...root, ...property, parent }));
            const uniqueTypes = types.filter(unique);
            let uniqueTypesString = uniqueTypes.join(' | ');
            if (uniqueTypes.length > 1) {
                uniqueTypesString = `(${uniqueTypesString})`;
            }
            return options.fn(uniqueTypesString);
        }
    );

    Handlebars.registerHelper(
        'intersection',
        function (this: any, properties: Model[], parent: string | undefined, options: Handlebars.HelperOptions) {
            const type = Handlebars.partials['type'];
            const types = properties.map(property => type({ ...root, ...property, parent }));
            const uniqueTypes = types.filter(unique);
            let uniqueTypesString = uniqueTypes.join(' & ');
            if (uniqueTypes.length > 1) {
                uniqueTypesString = `(${uniqueTypesString})`;
            }
            return options.fn(uniqueTypesString);
        }
    );

    Handlebars.registerHelper(
        'enumerator',
        function (
            this: any,
            enumerators: Enum[],
            parent: string | undefined,
            name: string | undefined,
            options: Handlebars.HelperOptions
        ) {
            if (!root.useUnionTypes && parent && name) {
                return `${parent}.${name}`;
            }
            return options.fn(
                enumerators
                    .map(enumerator => enumerator.value)
                    .filter(unique)
                    .join(' | ')
            );
        }
    );
}