Function validate

src/core/friendly_errors/param_validator.js:535–583

(func, args)

   * @returns {String} [result.error] - The validation error message if validation has failed.
   */
  const validate = function (func, args) {
    if (p5.disableFriendlyErrors) {
      return; // skip FES
    }

    if (!Array.isArray(args)) {
      args = Array.from(args);
    }

    // An edge case: even when all arguments are optional and therefore,
    // theoretically allowed to stay undefined and valid, it is likely that the
    // user intended to call the function with non-undefined arguments. Skip
    // regular workflow and return a friendly error message right away.
    if (
      Array.isArray(args) &&
      args.length > 0 &&
      args.every(arg => arg === undefined)
    ) {
      const undefinedErrorMessage = `🌸 p5.js says: All arguments for ${func}() are undefined. There is likely an error in the code.`;

      return {
        success: false,
        error: undefinedErrorMessage
      };
    }

    let funcSchemas = schemaRegistry.get(func);
    if (!funcSchemas) {
      funcSchemas = generateZodSchemasForFunc(func);
      if (!funcSchemas) return;
      schemaRegistry.set(func, funcSchemas);
    }

    try {
      return {
        success: true,
        data: funcSchemas.parse(args)
      };
    } catch (error) {
      const closestSchema = findClosestSchema(funcSchemas, args);
      const zodError = closestSchema.safeParse(args).error;
      const errorMessage = friendlyParamError(zodError, func, args);

      return {
        success: false,
        error: errorMessage
      };
    }
  };

  fn._validate = validate; // TEMP: For unit tests