Javascript 如何获取对象的所有属性？

如何使用JavaScript中的反射获取对象的所有属性？

循环遍历对象，并获取属于该对象的所有键和不属于该对象的所有键 功能：

var properties = [];
for(var key in obj) {
    if(obj.hasOwnProperty(key) && typeof obj[key] !== 'function') {
        properties.push(key);
    }
}

---

在现代浏览器中，要获取所有属性名（不仅仅是可枚举属性），您需要使用

Object.getOwnPropertyNames

var props = Object.getOwnPropertyNames(my_object)

var props = Object.keys(my_object)

如果您不想要可枚举属性，您可以使用

Object.keys

var props = Object.getOwnPropertyNames(my_object)

var props = Object.keys(my_object)

---

JavaScript没有用于反射（内省）的好的内置工具，因此需要手动创建

首先，这里是一个解决方案的代码

/**
 * Display details about an object at run-time
 * @param  {[any]} target Any object
 * @return Nothing, all information will be display
 */
const introspect = (target) => {
    // get type of a target
    const typeTarget = typeof target;

    // variable for type attribute of the target
    let typeAttr;

    // for properties and methods of the target
    let properties = [];
    let methods = [];

    // if target is array, keep names all enumerable properties, simple put - numbers of indexes
    // otherwise set to null
    const enumerableProperties = Array.isArray(target) ? Object.keys(target) : null;

    // determination functions and properties of the target by a parent object
    Object.getOwnPropertyNames(Object.getPrototypeOf(target)).forEach((name) => {
        if (typeof target[name] === 'function') {
            methods.push(name);
        } else if (target.hasOwnProperty(name) && properties.indexOf(name) === -1) {
            properties.push(name);
        }
    });

    // determination other functions and properties of the target
    // filter it, if a name already added or if it is an array - filter all values of the indexes
    Object.getOwnPropertyNames(target).forEach((name) => {
        if (enumerableProperties !== null && enumerableProperties.indexOf(name) !== -1) {
            return;
        }
        if (typeof target[name] === 'function') {
            methods.push(name);
        } else if (target.hasOwnProperty(name) && properties.indexOf(name) === -1) {
            properties.push(name);
        }
    });

    // order properties and methods by name in reverse
    properties = properties.reverse();
    methods = methods.reverse();

    // display an obtained information by groups
    console.log(`${typeTarget}: "${target}"`);
    console.log(`\n\tProperties: ${properties.length}\n\t------------------`);
    for (let i = properties.length - 1; i >= 0; i -= 1) {
        typeAttr = typeof target[properties[i]];
        console.log(`\t\t${properties[i]} --> ${typeAttr}`);
    }

    console.log(`\n\tMethods: ${methods.length}\n\t------------------`);
    for (let i = methods.length - 1; i >= 0; i -= 1) {
        let args = functools.getFunctionParameters(target[methods[i]]);
        args = args.join(', ');
        console.log(`\t\t${methods[i]} (${args})`);
    }
};

在实际示例中检查此函数

用于内置对象数组

introspect(Array);

introspect([-10, '20', true, []]);

结果:

function: "function Array() { [native code] }"

    Properties: 5
    ------------------
        length --> number
        name --> string
        arguments --> object
        caller --> object
        prototype --> object

    Methods: 8
    ------------------
        apply ()
        bind ()
        call ()
        toString ()
        constructor ()
        isArray ()
        from ()
        of ()

object: "-10,20,true,"

    Properties: 1
    ------------------
        length --> number

    Methods: 29
    ------------------
        constructor ()
        toString ()
        toLocaleString ()
        join ()
        pop ()
        push ()
        reverse ()
        shift ()
        unshift ()
        slice ()
        splice ()
        sort ()
        filter ()
        forEach ()
        some ()
        every ()
        map ()
        indexOf ()
        lastIndexOf ()
        reduce ()
        reduceRight ()
        copyWithin ()
        find ()
        findIndex ()
        fill ()
        includes ()
        entries ()
        keys ()
        concat ()

object: "[object Object]"

    Properties: 4
    ------------------
        aa --> number
        bb --> boolean
        cc --> object
        dd --> object

    Methods: 14
    ------------------
        hasOwnProperty ()
        constructor ()
        toString ()
        toLocaleString ()
        valueOf ()
        isPrototypeOf ()
        propertyIsEnumerable ()
        __defineGetter__ ()
        __lookupGetter__ ()
        __defineSetter__ ()
        __lookupSetter__ ()
        c (z, a = 2)
        b (z = 1, a = 2)
        d (b, zzz)

对于实数组（对象数组的实例）

结果:

function: "function Array() { [native code] }"

    Properties: 5
    ------------------
        length --> number
        name --> string
        arguments --> object
        caller --> object
        prototype --> object

    Methods: 8
    ------------------
        apply ()
        bind ()
        call ()
        toString ()
        constructor ()
        isArray ()
        from ()
        of ()

object: "-10,20,true,"

    Properties: 1
    ------------------
        length --> number

    Methods: 29
    ------------------
        constructor ()
        toString ()
        toLocaleString ()
        join ()
        pop ()
        push ()
        reverse ()
        shift ()
        unshift ()
        slice ()
        splice ()
        sort ()
        filter ()
        forEach ()
        some ()
        every ()
        map ()
        indexOf ()
        lastIndexOf ()
        reduce ()
        reduceRight ()
        copyWithin ()
        find ()
        findIndex ()
        fill ()
        includes ()
        entries ()
        keys ()
        concat ()

object: "[object Object]"

    Properties: 4
    ------------------
        aa --> number
        bb --> boolean
        cc --> object
        dd --> object

    Methods: 14
    ------------------
        hasOwnProperty ()
        constructor ()
        toString ()
        toLocaleString ()
        valueOf ()
        isPrototypeOf ()
        propertyIsEnumerable ()
        __defineGetter__ ()
        __lookupGetter__ ()
        __defineSetter__ ()
        __lookupSetter__ ()
        c (z, a = 2)
        b (z = 1, a = 2)
        d (b, zzz)

那么一个真实的物体呢

introspect({
    aa: 1,
    bb: true,
    cc: [],
    dd: {},
    c: (z, a= 2) => {},
    b: function(z   =  1, a=2) {},
    d: function(b, zzz) {},
});

结果:

function: "function Array() { [native code] }"

    Properties: 5
    ------------------
        length --> number
        name --> string
        arguments --> object
        caller --> object
        prototype --> object

    Methods: 8
    ------------------
        apply ()
        bind ()
        call ()
        toString ()
        constructor ()
        isArray ()
        from ()
        of ()

object: "-10,20,true,"

    Properties: 1
    ------------------
        length --> number

    Methods: 29
    ------------------
        constructor ()
        toString ()
        toLocaleString ()
        join ()
        pop ()
        push ()
        reverse ()
        shift ()
        unshift ()
        slice ()
        splice ()
        sort ()
        filter ()
        forEach ()
        some ()
        every ()
        map ()
        indexOf ()
        lastIndexOf ()
        reduce ()
        reduceRight ()
        copyWithin ()
        find ()
        findIndex ()
        fill ()
        includes ()
        entries ()
        keys ()
        concat ()

object: "[object Object]"

    Properties: 4
    ------------------
        aa --> number
        bb --> boolean
        cc --> object
        dd --> object

    Methods: 14
    ------------------
        hasOwnProperty ()
        constructor ()
        toString ()
        toLocaleString ()
        valueOf ()
        isPrototypeOf ()
        propertyIsEnumerable ()
        __defineGetter__ ()
        __lookupGetter__ ()
        __defineSetter__ ()
        __lookupSetter__ ()
        c (z, a = 2)
        b (z = 1, a = 2)
        d (b, zzz)

此功能也可以很好地与内置模块配合使用。对数学模块进行反思

introspect(Math);

结果

object: "[object Math]"

    Properties: 8
    ------------------
        E --> number
        LN10 --> number
        LN2 --> number
        LOG2E --> number
        LOG10E --> number
        PI --> number
        SQRT1_2 --> number
        SQRT2 --> number

    Methods: 46
    ------------------
        hasOwnProperty ()
        constructor ()
        toString ()
        toLocaleString ()
        valueOf ()
        isPrototypeOf ()
        propertyIsEnumerable ()
        __defineGetter__ ()
        __lookupGetter__ ()
        __defineSetter__ ()
        __lookupSetter__ ()
        acos ()
        asin ()
        atan ()
        ceil ()
        clz32 ()
        floor ()
        fround ()
        imul ()
        max ()
        min ()
        round ()
        sqrt ()
        trunc ()
        random ()
        abs ()
        exp ()
        log ()
        atan2 ()
        pow ()
        sign ()
        asinh ()
        acosh ()
        atanh ()
        hypot ()
        cbrt ()
        cos ()
        sin ()
        tan ()
        sinh ()
        cosh ()
        tanh ()
        log10 ()
        log2 ()
        log1p ()
        expm1 ()

不管什么污染了回答多余的代码，试着自己去做，看看结果如何

introspect(34.2313);
introspect(true);
introspect(Date);
introspect((new Date()));
introspect(String);
introspect('text');

对于完整的代码，我还展示了函数“getFunctionParameters”（在模块“functools.js”中），因为它使用了它

/**
 * Return array paraments of a function
 * @param  {[function]} func function
 * @return {[array]}      parameters the functions
 *
 */
const getFunctionParameters = (func) => {
    if (typeof func !== 'function') {
        throw new Error('A argument is not function.');
    }
    const args = func.toString().match(/\((.*)\)/)[1];
    return args.split(',').map((arg) => {
        if (arg.indexOf('=') === -1) return arg.trim();
        return arg
            .split('=')
            .map(val => val.trim())
            .join(' = ');
    });
};

注意事项：

弱测试

完整代码在这里

关于it主题的好资源

使用了ES6的功能

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可能重复的可能重复的@Brian Roach为什么是重复的？这与toString无关！没有什么真正的原因来解释obj[key]的类型函数“检查。方法也是属性。