Function createModuleTextFromProgram

typescript/src/ts/program.ts:86–136

(jsonObject: object)

 * couldn't be transformed.
 */
export function createModuleTextFromProgram(jsonObject: object): Result<string> {
    const steps = (jsonObject as Program)["@steps"];
    if (!(Array.isArray(steps) && steps.every(step => typeof step === "object" && step !== null && step.hasOwnProperty("@func")))) {
        return error("JSON object is not a valid program");
    }
    let hasError = false;
    let functionBody = "";
    let currentStep = 0;
    while (currentStep < steps.length) {
        functionBody += `  ${currentStep === steps.length - 1 ? `return` : `const step${currentStep + 1} =`} ${exprToString(steps[currentStep])};\n`;
        currentStep++;
    }
    return hasError ?
        error("JSON program contains an invalid expression") :
        success(`import { API } from "./schema";\nfunction program(api: API) {\n${functionBody}}`);

    function exprToString(expr: unknown): string {
        return typeof expr === "object" && expr !== null ?
            objectToString(expr as Record<string, unknown>) :
            JSON.stringify(expr);
    }

    function objectToString(obj: Record<string, unknown>) {
        if (obj.hasOwnProperty("@ref")) {
            const index = obj["@ref"];
            if (typeof index === "number" && index < currentStep && Object.keys(obj).length === 1) {
                return `step${index + 1}`;
            }
        }
        else if (obj.hasOwnProperty("@func")) {
            const func = obj["@func"];
            const hasArgs = obj.hasOwnProperty("@args");
            const args = hasArgs ? obj["@args"] : [];
            if (typeof func === "string" && (Array.isArray(args)) && Object.keys(obj).length === (hasArgs ? 2 : 1)) {
                return `api.${func}(${arrayToString(args)})`;
            }
        }
        else if (Array.isArray(obj)) {
            return `[${arrayToString(obj)}]`;
        }
        else {
            return `{ ${Object.keys(obj).map(key => `${JSON.stringify(key)}: ${exprToString(obj[key])}`).join(", ")} }`;
        }
        hasError = true;
        return "";
    }

    function arrayToString(array: unknown[]) {
        return array.map(exprToString).join(", ");
    }
}

/**
 * Evaluates a JSON program using a simple interpreter. Function calls in the program are passed to the `onCall`