arquero/src/helpers/escape.js

Query processing and transformation of array-backed data tables.

import { wrap } from './wrap.js';
import { error } from '../util/error.js';

/**
 * Escape a function or value to prevent it from being parsed and recompiled.
 * This helper can be used in lieu of single-table table expressions (which
 * are internally parsed and rewritten) to apply a JavaScript function as-is,
 * including support for closures. It can also be used to pass a constant,
 * literal value as a table expression, bypassing the parser.
 * @param {*} value A function or value to escape.
 * @return {object} A wrapper object representing the escaped value.
 * @example escape(d => d.a.toFixed(2))
 * @example escape(d => d.a * -d.b)
 */
export function escape(value) {
  return wrap(value, {
    escape: true,
    toString() { error('Escaped values can not be serialized.'); }
  });
}