jsondiffpatch/src/filters/trivial.js

Diff & Patch for Javascript objects

var isArray = (typeof Array.isArray === 'function') ?
  // use native function
  Array.isArray :
  // use instanceof operator
  function(a) {
    return a instanceof Array;
  };

var diffFilter = function trivialMatchesDiffFilter(context) {
  if (context.left === context.right) {
    context.setResult(undefined).exit();
    return;
  }
  if (typeof context.left === 'undefined') {
    if (typeof context.right === 'function') {
      throw new Error('functions are not supported');
    }
    context.setResult([context.right]).exit();
    return;
  }
  if (typeof context.right === 'undefined') {
    context.setResult([context.left, 0, 0]).exit();
    return;
  }
  if (typeof context.left === 'function' || typeof context.right === 'function') {
    throw new Error('functions are not supported');
  }
  context.leftType = context.left === null ? 'null' : typeof context.left;
  context.rightType = context.right === null ? 'null' : typeof context.right;
  if (context.leftType !== context.rightType) {
    context.setResult([context.left, context.right]).exit();
    return;
  }
  if (context.leftType === 'boolean' || context.leftType === 'number') {
    context.setResult([context.left, context.right]).exit();
    return;
  }
  if (context.leftType === 'object') {
    context.leftIsArray = isArray(context.left);
  }
  if (context.rightType === 'object') {
    context.rightIsArray = isArray(context.right);
  }
  if (context.leftIsArray !== context.rightIsArray) {
    context.setResult([context.left, context.right]).exit();
    return;
  }

  if (context.left instanceof RegExp) {
    if (context.right instanceof RegExp) {
      context.setResult([context.left.toString(), context.right.toString()]).exit();
    } else {
      context.setResult([context.left, context.right]).exit();
      return;
    }
  }
};
diffFilter.filterName = 'trivial';

var patchFilter = function trivialMatchesPatchFilter(context) {
  if (typeof context.delta === 'undefined') {
    context.setResult(context.left).exit();
    return;
  }
  context.nested = !isArray(context.delta);
  if (context.nested) {
    return;
  }
  if (context.delta.length === 1) {
    context.setResult(context.delta[0]).exit();
    return;
  }
  if (context.delta.length === 2) {
    if (context.left instanceof RegExp) {
      var regexArgs = /^\/(.*)\/([gimyu]+)$/.exec(context.delta[1]);
      if (regexArgs) {
        context.setResult(new RegExp(regexArgs[1], regexArgs[2])).exit();
        return;
      }
    }
    context.setResult(context.delta[1]).exit();
    return;
  }
  if (context.delta.length === 3 && context.delta[2] === 0) {
    context.setResult(undefined).exit();
    return;
  }
};
patchFilter.filterName = 'trivial';

var reverseFilter = function trivialReferseFilter(context) {
  if (typeof context.delta === 'undefined') {
    context.setResult(context.delta).exit();
    return;
  }
  context.nested = !isArray(context.delta);
  if (context.nested) {
    return;
  }
  if (context.delta.length === 1) {
    context.setResult([context.delta[0], 0, 0]).exit();
    return;
  }
  if (context.delta.length === 2) {
    context.setResult([context.delta[1], context.delta[0]]).exit();
    return;
  }
  if (context.delta.length === 3 && context.delta[2] === 0) {
    context.setResult([context.delta[0]]).exit();
    return;
  }
};
reverseFilter.filterName = 'trivial';

exports.diffFilter = diffFilter;
exports.patchFilter = patchFilter;
exports.reverseFilter = reverseFilter;