nock/dist/lib/stringify.js

HTTP server mocking and expectations library for Node.js

/**
 * @module stringify
 * @private
 * Safe JSON.stringify that handles circular references.
 * @see https://github.com/moll/json-stringify-safe/blob/02cfafd45f06d076ac4bf0dd28be6738a07a72f9/stringify.js
 * @license
 * The ISC License
 *
 * Copyright (c) Isaac Z. Schlueter and Contributors
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
 * IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

function stringify(obj     ) {
  return JSON.stringify(obj, safeReplacer())
}

function cycleReplacer(stack       , keys          , value     ) {
  if (stack[0] === value) return '[Circular ~]'
  return `[Circular ~.${keys.slice(0, stack.indexOf(value)).join('.')}]`
}

function safeReplacer(stack        = [], keys           = []) {
  return function (           key        , value     ) {
    if (stack.length > 0) {
      const thisPos = stack.indexOf(this)
      ~thisPos ? stack.splice(thisPos + 1) : stack.push(this)
      ~thisPos ? keys.splice(thisPos, Infinity, key) : keys.push(key)
      if (~stack.indexOf(value)) {
        value = cycleReplacer(stack, keys, value)
      }
    } else {
      stack.push(value)
    }

    return value
  }
}

export default stringify