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1module.exports = {2  diffApply: diffApply,3  jsonPatchPathConverter: jsonPatchPathConverter,4};5 6/*7  const obj1 = {a: 3, b: 5};8  diffApply(obj1,9    [10      { "op": "remove", "path": ['b'] },11      { "op": "replace", "path": ['a'], "value": 4 },12      { "op": "add", "path": ['c'], "value": 5 }13    ]14  );15  obj1; // {a: 4, c: 5}16 17  // using converter to apply jsPatch standard paths18  // see http://jsonpatch.com19  import {diff, jsonPatchPathConverter} from 'just-diff'20  const obj2 = {a: 3, b: 5};21  diffApply(obj2, [22    { "op": "remove", "path": '/b' },23    { "op": "replace", "path": '/a', "value": 4 }24    { "op": "add", "path": '/c', "value": 5 }25  ], jsonPatchPathConverter);26  obj2; // {a: 4, c: 5}27 28  // arrays29  const obj3 = {a: 4, b: [1, 2, 3]};30  diffApply(obj3, [31    { "op": "replace", "path": ['a'], "value": 3 }32    { "op": "replace", "path": ['b', 2], "value": 4 }33    { "op": "add", "path": ['b', 3], "value": 9 }34  ]);35  obj3; // {a: 3, b: [1, 2, 4, 9]}36 37  // nested paths38  const obj4 = {a: 4, b: {c: 3}};39  diffApply(obj4, [40    { "op": "replace", "path": ['a'], "value": 5 }41    { "op": "remove", "path": ['b', 'c']}42    { "op": "add", "path": ['b', 'd'], "value": 4 }43  ]);44  obj4; // {a: 5, b: {d: 4}}45*/46 47var REMOVE = 'remove';48var REPLACE = 'replace';49var ADD = 'add';50var MOVE = 'move';51 52function diffApply(obj, diff, pathConverter) {53  if (!obj || typeof obj != 'object') {54    throw new Error('base object must be an object or an array');55  }56 57  if (!Array.isArray(diff)) {58    throw new Error('diff must be an array');59  }60 61  var diffLength = diff.length;62  for (var i = 0; i < diffLength; i++) {63    var thisDiff = diff[i];64    var subObject = obj;65    var thisOp = thisDiff.op;66 67    var thisPath = transformPath(pathConverter, thisDiff.path);68    var thisFromPath = thisDiff.from && transformPath(pathConverter, thisDiff.from);69    var toPath, toPathCopy, lastToProp, subToObject, valueToMove;70 71    if (thisFromPath) {72      // MOVE only, "fromPath" is effectively path and "path" is toPath73      toPath = thisPath;74      thisPath = thisFromPath;75 76      toPathCopy = toPath.slice();77      lastToProp = toPathCopy.pop();78      prototypeCheck(lastToProp);79      if (lastToProp == null) {80        return false;81      }82 83      var thisToProp;84      while (((thisToProp = toPathCopy.shift())) != null) {85        prototypeCheck(thisToProp);86        if (!(thisToProp in subToObject)) {87          subToObject[thisToProp] = {};88        }89        subToObject = subToObject[thisToProp];90      }91    }92 93    var pathCopy = thisPath.slice();94    var lastProp = pathCopy.pop();95    prototypeCheck(lastProp);96    if (lastProp == null) {97      return false;98    }99 100    var thisProp;101    while (((thisProp = pathCopy.shift())) != null) {102      prototypeCheck(thisProp);103      if (!(thisProp in subObject)) {104        subObject[thisProp] = {};105      }106      subObject = subObject[thisProp];107    }108    if (thisOp === REMOVE || thisOp === REPLACE || thisOp === MOVE) {109      var path = thisOp === MOVE ? thisDiff.from : thisDiff.path;110      if (!subObject.hasOwnProperty(lastProp)) {111        throw new Error(['expected to find property', path, 'in object', obj].join(' '));112      }113    }114    if (thisOp === REMOVE || thisOp === MOVE) {115      if (thisOp === MOVE) {116        valueToMove = subObject[lastProp];117      }118      Array.isArray(subObject) ? subObject.splice(lastProp, 1) : delete subObject[lastProp];119    }120    if (thisOp === REPLACE || thisOp === ADD) {121      subObject[lastProp] = thisDiff.value;122    }123 124    if (thisOp === MOVE) {125      subObject[lastToProp] = valueToMove;126    }127  }128  return subObject;129}130 131function transformPath(pathConverter, thisPath) {132  if(pathConverter) {133    thisPath = pathConverter(thisPath);134    if(!Array.isArray(thisPath)) {135      throw new Error([136        'pathConverter must return an array, returned:',137        thisPath,138      ].join(' '));139    }140  } else {141    if(!Array.isArray(thisPath)) {142      throw new Error([143        'diff path',144        thisPath,145        'must be an array, consider supplying a path converter']146        .join(' '));147    }148  }149  return thisPath;150}151 152function jsonPatchPathConverter(stringPath) {153  return stringPath.split('/').slice(1);154}155 156function prototypeCheck(prop) {157  // coercion is intentional to catch prop values like `['__proto__']`158  if (prop == '__proto__' || prop == 'constructor' || prop == 'prototype') {159    throw new Error('setting of prototype values not supported');160  }161}162