packages/node_modules/pouchdb-adapter-indexeddb/src/rewrite.js

'use strict';

var IDB_NULL = Number.MIN_SAFE_INTEGER;
var IDB_FALSE = Number.MIN_SAFE_INTEGER + 1;
var IDB_TRUE = Number.MIN_SAFE_INTEGER + 2;

//
// IndexedDB only allows valid JS names in its index paths, whereas JSON allows
// for any string at all. This converts invalid JS names to valid ones, to allow
// for them to be indexed.
//
// For example, "foo-bar" is a valid JSON key, but cannot be a valid JS name
// (because that would be read as foo minus bar).
//
// Very high level rules for valid JS names are:
//  - First character cannot start with a number
//  - Otherwise all characters must be be a-z, A-Z, 0-9, $ or _.
//  - We allow . unless the name represents a single field, as that represents
//    a deep index path.
//
// This is more aggressive than it needs to be, but also simpler.
//
var KEY_INVALID = /[^a-zA-Z0-9_$]+|(^[^a-zA-Z_$])/g;
var PATH_INVALID = /(\\.)|[^a-zA-Z0-9_$.]+|(^[^a-zA-Z_$])/g;
var SLASH = '\\'.charCodeAt(0);

// These are the same as above but without the global flag
// we want to use RegExp.test because it's really fast, but the global flag
// makes the regex const stateful (seriously) as it walked through all instances
var TEST_KEY_INVALID = /[^a-zA-Z0-9_$]+|(^[^a-zA-Z_$])/;
var TEST_PATH_INVALID = /(\\.)|[^a-zA-Z0-9_$.]+|(^[^a-zA-Z_$])/;
function needsSanitise(name, isPath) {
  if (isPath) {
    return TEST_PATH_INVALID.test(name);
  } else {
    return TEST_KEY_INVALID.test(name);
  }
}

function sanitise(name, isPath) {
  var correctCharacters = function (match) {
    var good = '';
    for (var i = 0; i < match.length; i++) {
      var code = match.charCodeAt(i);
      // If you're sanitising a path, a slash character is there to be interpreted
      // by whatever parses the path later as "escape the next thing".
      //
      // e.g., if you want to index THIS string:
      //   {"foo": {"bar.baz": "THIS"}}
      // Your index path would be "foo.bar\.baz".
      if (code === SLASH && isPath) {
        continue;
      }

      good += '_c' + code + '_';
    }
    return good;
  };

  if (isPath) {
    return name.replace(PATH_INVALID, correctCharacters);
  } else {
    return name.replace(KEY_INVALID, correctCharacters);
  }
}

function needsRewrite(data) {
  for (var key of Object.keys(data)) {
    if (needsSanitise(key)) {
      return true;
    } else if (data[key] === null || typeof data[key] === 'boolean') {
      return true;
    } else if (typeof data[key] === 'object') {
      return needsRewrite(data[key]);
    }
  }
}

function rewrite(data) {
  if (!needsRewrite(data)) {
    return false;
  }

  var isArray = Array.isArray(data);
  var clone = isArray
    ? []
    : {};

  Object.keys(data).forEach(function (key) {
    var safeKey = isArray ? key : sanitise(key);

    if (data[key] === null) {
      clone[safeKey] = IDB_NULL;
    } else if (typeof data[key] === 'boolean') {
      clone[safeKey] = data[key] ? IDB_TRUE : IDB_FALSE;
    } else if (typeof data[key] === 'object') {
      clone[safeKey] = rewrite(data[key]);
    } else {
      clone[safeKey] = data[key];
    }
  });

  return clone;
}

export {
  IDB_NULL,
  IDB_TRUE,
  IDB_FALSE,
  rewrite,
  sanitise
};