@enspirit/emb/dist/src/utils/TemplateExpander.js

A replacement for our Makefile-for-monorepos

const TPL_REGEX = /(?<!\\)\${(?:(\w+):)?(\w+)(?::-(.*?))?}/g;
export class TemplateExpander {
    expansions = [];
    get expansionCount() {
        return this.expansions.length;
    }
    async expand(str, options = {}) {
        return (str || '')
            .toString()
            .replaceAll(TPL_REGEX, (match, source, key, fallback) => {
            const src = source ?? options.default ?? '';
            const provider = options.sources?.[src];
            if (!provider) {
                if (fallback !== undefined) {
                    return this.track(src, key, fallback);
                }
                throw new Error(`Invalid expand provider '${source}' ('${match}')`);
            }
            const val = provider[key];
            if (!val && fallback === undefined) {
                throw new Error(`Could not expand '${match}' and no default value provided`);
            }
            if (val !== undefined && val !== null) {
                return this.track(src, key, val);
            }
            return this.track(src, key, fallback ?? '');
        })
            .replaceAll('\\${', '${');
    }
    async expandRecord(record, options) {
        if (typeof record === 'string') {
            const out = await this.expand(record, options);
            return out;
        }
        if (Array.isArray(record)) {
            const out = await Promise.all(record.map((v) => this.expandRecord(v, options)));
            return out;
        }
        const entries = await Promise.all(Object.entries(record).map(async ([k, v]) => {
            const expandedValue = await this.expandRecord(v, options);
            return [k, expandedValue];
        }));
        return Object.fromEntries(entries);
    }
    track(source, variable, value) {
        this.expansions.push({ source, value, variable });
        return String(value);
    }
}