我正在尝试遍历对象中的每个键并将其打印出来，就像JSON.stringify将其输出为
看起来像
{
"name": "james",
"profile": {
"location": "ireland",
"address": {
"city": "dublin"
},
"hobbies": {}
}
}
到目前为止，它的输出为
"name": "James",
"profile": {
"location": "ireland",
"address": {
"city": "dublin",
}
const output = (data, node) => {
for (let key in data) {
if (typeof data[key] === 'object' && Object.keys(data[key]).length > 0) {
if (node === true) {
console.log(` "${key}": {`)
} else {
console.log(`"${key}": {`)
}
output(data[key], true)
} else {
console.log(`"${key}": "${Object.keys(data[key]).length > 0 ? data[key] : '{}' }",`);
}
}
console.log(`}`)
}
const obj = {
"name": "James",
"profile": {
"location": "ireland",
"address": {
"city": "dublin"
},
"hobbies": {}
}
};
output(obj);
如何为对象内部的每个键正确输出选项卡？
答案 0 :(得分：1)
它仍然需要工作，但是您需要在缩进级别上保持跟踪。简单的方法就是传递它，而不是生成选项卡的数量。
const output = (data, node, indent = 0) => {
const tabs = Array(indent).fill('\t').join('')
const tabsClose = indent ? Array(indent-1).fill('\t').join('') : ''
for (let key in data) {
if (typeof data[key] === 'object' && Object.keys(data[key]).length > 0) {
if (node === true) {
console.log(`${tabs}"${key}": {`)
} else {
console.log(`${tabs}"${key}": {`)
}
output(data[key], true, indent + 1)
} else {
console.log(`${tabs}"${key}": "${Object.keys(data[key]).length > 0 ? data[key] : '{}' }",`);
}
}
console.log(`${tabsClose}}`)
}
const obj = {
"name": "James",
"profile": {
"location": "ireland",
"address": {
"city": "dublin"
},
"hobbies": {}
}
};
output(obj);
与您的代码有关的问题是您不考虑右括号，并且末尾有逗号。
答案 1 :(得分：1)
JSON.stringify是一个COMPLEX方法，需要考虑很多边缘情况。此解决方案可能位于棒球场，改编自BestieJS。签名是stringify(value, replacerFunction, space)，就像原始的JSON.stringify一样。
let charIndexBuggy = has("bug-string-char-index");
const functionClass = "[object Function]",
dateClass = "[object Date]",
numberClass = "[object Number]",
stringClass = "[object String]",
arrayClass = "[object Array]",
booleanClass = "[object Boolean]";
function stringify(source, filter, width) {
var whitespace, callback, properties, className;
// A set of types used to distinguish objects from primitives.
var objectTypes = {
"function": true,
"object": true
};
if (objectTypes[typeof filter] && filter) {
if ((className = Object.prototype.toString.call(filter)) == functionClass) {
callback = filter;
} else if (className == arrayClass) {
// Convert the property names array into a makeshift set.
properties = {};
for (var index = 0, length = filter.length, value; index < length; value = filter[index++], ((className = Object.prototype.toString.call(value)), className == stringClass || className == numberClass) && (properties[value] = 1));
}
}
if (width) {
if ((className = Object.prototype.toString.call(width)) == numberClass) {
// Convert the `width` to an integer and create a string containing
// `width` number of space characters.
if ((width -= width % 1) > 0) {
for (whitespace = "", width > 10 && (width = 10); whitespace.length < width; whitespace += " ");
}
} else if (className == stringClass) {
whitespace = width.length <= 10 ? width : width.slice(0, 10);
}
}
// Opera <= 7.54u2 discards the values associated with empty string keys
// (`""`) only if they are used directly within an object member list
// (e.g., `!("" in { "": 1})`).
return serialize("", (value = {}, value[""] = source, value), callback, properties, whitespace, "", []);
};
// Internal: Recursively serializes an object. Implements the
// `Str(key, holder)`, `JO(value)`, and `JA(value)` operations.
function serialize(property, object, callback, properties, whitespace, indentation, stack) {
let value, className, year, month, date, time, hours, minutes, seconds, milliseconds, results, element, index, length, prefix, result, isProperty;
var functionClass = "[object Function]",
dateClass = "[object Date]",
numberClass = "[object Number]",
stringClass = "[object String]",
arrayClass = "[object Array]",
booleanClass = "[object Boolean]";
try {
// Necessary for host object support.
value = object[property];
} catch (exception) { }
if (typeof value == "object" && value) {
className = Object.prototype.toString.call(value);
if (className == dateClass && !isProperty.call(value, "toJSON")) {
if (value > -1 / 0 && value < 1 / 0) {
// Dates are serialized according to the `Date#toJSON` method
// specified in ES 5.1 section 15.9.5.44. See section 15.9.1.15
// for the ISO 8601 date time string format.
if (getDay) {
// Manually compute the year, month, date, hours, minutes,
// seconds, and milliseconds if the `getUTC*` methods are
// buggy. Adapted from @Yaffle's `date-shim` project.
date = floor(value / 864e5);
for (year = floor(date / 365.2425) + 1970 - 1; getDay(year + 1, 0) <= date; year++);
for (month = floor((date - getDay(year, 0)) / 30.42); getDay(year, month + 1) <= date; month++);
date = 1 + date - getDay(year, month);
// The `time` value specifies the time within the day (see ES
// 5.1 section 15.9.1.2). The formula `(A % B + B) % B` is used
// to compute `A modulo B`, as the `%` operator does not
// correspond to the `modulo` operation for negative numbers.
time = (value % 864e5 + 864e5) % 864e5;
// The hours, minutes, seconds, and milliseconds are obtained by
// decomposing the time within the day. See section 15.9.1.10.
hours = floor(time / 36e5) % 24;
minutes = floor(time / 6e4) % 60;
seconds = floor(time / 1e3) % 60;
milliseconds = time % 1e3;
} else {
year = value.getUTCFullYear();
month = value.getUTCMonth();
date = value.getUTCDate();
hours = value.getUTCHours();
minutes = value.getUTCMinutes();
seconds = value.getUTCSeconds();
milliseconds = value.getUTCMilliseconds();
}
// Serialize extended years correctly.
value = (year <= 0 || year >= 1e4 ? (year < 0 ? "-" : "+") + toPaddedString(6, year < 0 ? -year : year) : toPaddedString(4, year)) +
"-" + toPaddedString(2, month + 1) + "-" + toPaddedString(2, date) +
// Months, dates, hours, minutes, and seconds should have two
// digits; milliseconds should have three.
"T" + toPaddedString(2, hours) + ":" + toPaddedString(2, minutes) + ":" + toPaddedString(2, seconds) +
// Milliseconds are optional in ES 5.0, but required in 5.1.
"." + toPaddedString(3, milliseconds) + "Z";
} else {
value = null;
}
} else if (typeof value.toJSON == "function" && ((className != numberClass && className != stringClass && className != arrayClass) || isProperty.call(value, "toJSON"))) {
// Prototype <= 1.6.1 adds non-standard `toJSON` methods to the
// `Number`, `String`, `Date`, and `Array` prototypes. JSON 3
// ignores all `toJSON` methods on these objects unless they are
// defined directly on an instance.
value = value.toJSON(property);
}
}
if (callback) {
// If a replacement function was provided, call it to obtain the value
// for serialization.
value = callback.call(object, property, value);
}
if (value === null) {
return "null";
}
className = Object.prototype.toString.call(value);
if (className == booleanClass) {
// Booleans are represented literally.
return "" + value;
} else if (className == numberClass) {
// JSON numbers must be finite. `Infinity` and `NaN` are serialized as
// `"null"`.
return value > -1 / 0 && value < 1 / 0 ? "" + value : "null";
} else if (className == stringClass) {
// Strings are double-quoted and escaped.
return quote("" + value);
}
// Recursively serialize objects and arrays.
if (typeof value == "object") {
// Check for cyclic structures. This is a linear search; performance
// is inversely proportional to the number of unique nested objects.
for (length = stack.length; length--;) {
if (stack[length] === value) {
// Cyclic structures cannot be serialized by `JSON.stringify`.
throw TypeError();
}
}
// Add the object to the stack of traversed objects.
stack.push(value);
results = [];
// Save the current indentation level and indent one additional level.
prefix = indentation;
indentation += whitespace;
if (className == arrayClass) {
// Recursively serialize array elements.
for (index = 0, length = value.length; index < length; index++) {
element = serialize(index, value, callback, properties, whitespace, indentation, stack);
results.push(element === undefined ? "null" : element);
}
result = results.length ? (whitespace ? "[\n" + indentation + results.join(",\n" + indentation) + "\n" + prefix + "]" : ("[" + results.join(",") + "]")) : "[]";
} else {
// Recursively serialize object members. Members are selected from
// either a user-specified list of property names, or the object
// itself.
forEach(properties || value, function(property) {
var element = serialize(property, value, callback, properties, whitespace, indentation, stack);
if (element !== undefined) {
// According to ES 5.1 section 15.12.3: "If `gap` {whitespace}
// is not the empty string, let `member` {quote(property) + ":"}
// be the concatenation of `member` and the `space` character."
// The "`space` character" refers to the literal space
// character, not the `space` {width} argument provided to
// `JSON.stringify`.
results.push(quote(property) + ":" + (whitespace ? " " : "") + element);
}
});
result = results.length ? (whitespace ? "{\n" + indentation + results.join(",\n" + indentation) + "\n" + prefix + "}" : ("{" + results.join(",") + "}")) : "{}";
}
// Remove the object from the traversed object stack.
stack.pop();
return result;
}
};
function quote(value) {
var result = '"', index = 0, length = value.length, useCharIndex = !charIndexBuggy || length > 10;
var symbols = useCharIndex && (charIndexBuggy ? value.split("") : value);
for (; index < length; index++) {
var charCode = value.charCodeAt(index);
// If the character is a control character, append its Unicode or
// shorthand escape sequence; otherwise, append the character as-is.
switch (charCode) {
case 8: case 9: case 10: case 12: case 13: case 34: case 92:
result += Escapes[charCode];
break;
default:
if (charCode < 32) {
result += unicodePrefix + toPaddedString(2, charCode.toString(16));
break;
}
result += useCharIndex ? symbols[index] : value.charAt(index);
}
}
return result + '"';
};
function has(name) {
if (has[name] !== undefined) {
// Return cached feature test result.
return has[name];
}
var isSupported;
if (name == "bug-string-char-index") {
// IE <= 7 doesn't support accessing string characters using square
// bracket notation. IE 8 only supports this for primitives.
isSupported = "a"[0] != "a";
} else if (name == "json") {
// Indicates whether both `JSON.stringify` and `JSON.parse` are
// supported.
isSupported = has("json-stringify") && has("json-parse");
} else {
var value, serialized = '{"a":[1,true,false,null,"\\u0000\\b\\n\\f\\r\\t"]}';
// Test `JSON.stringify`.
if (name == "json-stringify") {
var stringify = exports.stringify, stringifySupported = typeof stringify == "function" && isExtended;
if (stringifySupported) {
// A test function object with a custom `toJSON` method.
(value = function() {
return 1;
}).toJSON = value;
try {
stringifySupported =
// Firefox 3.1b1 and b2 serialize string, number, and boolean
// primitives as object literals.
stringify(0) === "0" &&
// FF 3.1b1, b2, and JSON 2 serialize wrapped primitives as object
// literals.
stringify(new Number()) === "0" &&
stringify(new String()) == '""' &&
// FF 3.1b1, 2 throw an error if the value is `null`, `undefinedined`, or
// does not define a canonical JSON representation (this applies to
// objects with `toJSON` properties as well, *unless* they are nested
// within an object or array).
stringify(Object.prototype.toString) === undefined &&
// IE 8 serializes `undefinedined` as `"undefinedined"`. Safari <= 5.1.7 and
// FF 3.1b3 pass this test.
stringify(undefined) === undefined &&
// Safari <= 5.1.7 and FF 3.1b3 throw `Error`s and `TypeError`s,
// respectively, if the value is omitted entirely.
stringify() === undefined &&
// FF 3.1b1, 2 throw an error if the given value is not a number,
// string, array, object, Boolean, or `null` literal. This applies to
// objects with custom `toJSON` methods as well, unless they are nested
// inside object or array literals. YUI 3.0.0b1 ignores custom `toJSON`
// methods entirely.
stringify(value) === "1" &&
stringify([value]) == "[1]" &&
// Prototype <= 1.6.1 serializes `[undefinedined]` as `"[]"` instead of
// `"[null]"`.
stringify([undefined]) == "[null]" &&
// YUI 3.0.0b1 fails to serialize `null` literals.
stringify(null) == "null" &&
// FF 3.1b1, 2 halts serialization if an array contains a function:
// `[1, true, Object.prototype.toString, 1]` serializes as "[1,true,],". FF 3.1b3
// elides non-JSON values from objects and arrays, unless they
// define custom `toJSON` methods.
stringify([undefined, Object.prototype.toString, null]) == "[null,null,null]" &&
// Simple serialization test. FF 3.1b1 uses Unicode escape sequences
// where character escape codes are expected (e.g., `\b` => `\u0008`).
stringify({ "a": [value, true, false, null, "\x00\b\n\f\r\t"] }) == serialized &&
// FF 3.1b1 and b2 ignore the `filter` and `width` arguments.
stringify(null, value) === "1" &&
stringify([1, 2], null, 1) == "[\n 1,\n 2\n]" &&
// JSON 2, Prototype <= 1.7, and older WebKit builds incorrectly
// serialize extended years.
stringify(new Date(-8.64e15)) == '"-271821-04-20T00:00:00.000Z"' &&
// The milliseconds are optional in ES 5, but required in 5.1.
stringify(new Date(8.64e15)) == '"+275760-09-13T00:00:00.000Z"' &&
// Firefox <= 11.0 incorrectly serializes years prior to 0 as negative
// four-digit years instead of six-digit years. Credits: @Yaffle.
stringify(new Date(-621987552e5)) == '"-000001-01-01T00:00:00.000Z"' &&
// Safari <= 5.1.5 and Opera >= 10.53 incorrectly serialize millisecond
// values less than 1000. Credits: @Yaffle.
stringify(new Date(-1)) == '"1969-12-31T23:59:59.999Z"';
} catch (exception) {
stringifySupported = false;
}
}
isSupported = stringifySupported;
}
// Test `JSON.parse`.
if (name == "json-parse") {
var parse = exports.parse;
if (typeof parse == "function") {
try {
// FF 3.1b1, b2 will throw an exception if a bare literal is provided.
// Conforming implementations should also coerce the initial argument to
// a string prior to parsing.
if (parse("0") === 0 && !parse(false)) {
// Simple parsing test.
value = parse(serialized);
var parseSupported = value["a"].length == 5 && value["a"][0] === 1;
if (parseSupported) {
try {
// Safari <= 5.1.2 and FF 3.1b1 allow unescaped tabs in strings.
parseSupported = !parse('"\t"');
} catch (exception) { }
if (parseSupported) {
try {
// FF 4.0 and 4.0.1 allow leading `+` signs and leading
// decimal points. FF 4.0, 4.0.1, and IE 9-10 also allow
// certain octal literals.
parseSupported = parse("01") !== 1;
} catch (exception) { }
}
if (parseSupported) {
try {
// FF 4.0, 4.0.1, and Rhino 1.7R3-R4 allow trailing decimal
// points. These environments, along with FF 3.1b1 and 2,
// also allow trailing commas in JSON objects and arrays.
parseSupported = parse("1.") !== 1;
} catch (exception) { }
}
}
}
} catch (exception) {
parseSupported = false;
}
}
isSupported = parseSupported;
}
}
return has[name] = !!isSupported;
}
function forEach(object, callback) {
var size = 0, Properties, members, property;
// Tests for bugs in the current environment's `for...in` algorithm. The
// `valueOf` property inherits the non-enumerable flag from
// `Object.prototype` in older versions of IE, Netscape, and Mozilla.
(Properties = function() {
this.valueOf = 0;
}).prototype.valueOf = 0;
// Iterate over a new instance of the `Properties` class.
members = new Properties();
for (property in members) {
// Ignore all properties inherited from `Object.prototype`.
if (isProperty.call(members, property)) {
size++;
}
}
Properties = members = null;
// Normalize the iteration algorithm.
if (!size) {
// A list of non-enumerable properties inherited from `Object.prototype`.
members = ["valueOf", "toString", "toLocaleString", "propertyIsEnumerable", "isPrototypeOf", "hasOwnProperty", "constructor"];
// IE <= 8, Mozilla 1.0, and Netscape 6.2 ignore shadowed non-enumerable
// properties.
forEach = function(object, callback) {
var isFunction = Object.prototype.toString.call(object) == functionClass, property, length;
var hasProperty = !isFunction && typeof object.constructor != "function" && objectTypes[typeof object.hasOwnProperty] && object.hasOwnProperty || isProperty;
for (property in object) {
// Gecko <= 1.0 enumerates the `prototype` property of functions under
// certain conditions; IE does not.
if (!(isFunction && property == "prototype") && hasProperty.call(object, property)) {
callback(property);
}
}
// Manually invoke the callback for each non-enumerable property.
for (length = members.length; property = members[--length]; hasProperty.call(object, property) && callback(property));
};
} else if (size == 2) {
// Safari <= 2.0.4 enumerates shadowed properties twice.
forEach = function(object, callback) {
// Create a set of iterated properties.
var members = {}, isFunction = Object.prototype.toString.call(object) == functionClass, property;
for (property in object) {
// Store each property name to prevent double enumeration. The
// `prototype` property of functions is not enumerated due to cross-
// environment inconsistencies.
if (!(isFunction && property == "prototype") && !isProperty.call(members, property) && (members[property] = 1) && isProperty.call(object, property)) {
callback(property);
}
}
};
} else {
// No bugs detected; use the standard `for...in` algorithm.
forEach = function(object, callback) {
var isFunction = Object.prototype.toString.call(object) == functionClass, property, isConstructor;
for (property in object) {
if (!(isFunction && property == "prototype") && isProperty.call(object, property) && !(isConstructor = property === "constructor")) {
callback(property);
}
}
// Manually invoke the callback for the `constructor` property due to
// cross-environment inconsistencies.
if (isConstructor || isProperty.call(object, (property = "constructor"))) {
callback(property);
}
};
}
return forEach(object, callback);
};
function isProperty(property) {
var members = {}, constructor;
if ((members.__proto__ = null, members.__proto__ = {
// The *proto* property cannot be set multiple times in recent
// versions of Firefox and SeaMonkey.
"toString": 1
}, members).toString != Object.prototype.toString) {
// Safari <= 2.0.3 doesn't implement `Object#hasOwnProperty`, but
// supports the mutable *proto* property.
isProperty = function(property) {
// Capture and break the object's prototype chain (see section 8.6.2
// of the ES 5.1 spec). The parenthesized expression prevents an
// unsafe transformation by the Closure Compiler.
var original = this.__proto__, result = property in (this.__proto__ = null, this);
// Restore the original prototype chain.
this.__proto__ = original;
return result;
};
} else {
// Capture a reference to the top-level `Object` constructor.
constructor = members.constructor;
// Use the `constructor` property to simulate `Object#hasOwnProperty` in
// other environments.
isProperty = function(property) {
var parent = (this.constructor || constructor).prototype;
return property in this && !(property in parent && this[property] === parent[property]);
};
}
members = null;
return isProperty.call(this, property);
};