我们现在有了选项as const，这是@phil294提到的第一个选项（嵌套的readonly）的语法简洁方式。

const a = {
    b: 33,
    c: [78, 99],
    d:{e:{f:{g:true, h:{boom:'selecta'}}}}
} as const;

a.d.e.f.h.boom = 'respek'; //Cannot assign to 'boom' because it is a read-only property.ts(2540)

作为一个额外的好处，你可以使用这个技巧使嵌套函数的输入不可变：

type ImmutableObject<T> = {
  readonly [K in keyof T]: Immutable<T[K]>;
}

export type Immutable<T> = {
  readonly [K in keyof T]: T[K] extends Function ? T[K] : ImmutableObject<T[K]>;
}

所以才会发生这种事

const a = {
    b: 33,
    c: [78, 99],
    d:{e:{f:{g:true, h:{boom:'selecta'}}}}
}

function mutateImmutable(input: Immutable<typeof a>) {
    input.d.e.f.h.boom = 'respek'; //Cannot assign to 'boom' because it is a read-only property.ts(2540)
}

如https://www.typescriptlang.org/docs/handbook/interfaces.html中所述，您可以在类/接口属性上使用readonly，或在不可变对象和数组上使用Readonly<...>/ReadonlyArray<>。在您的示例中，这看起来如下所示：

const a: Readonly<{
    b: number,
    c: ReadonlyArray<number>,
    d: Readonly<{
        e: Readonly<{
            f: Readonly<{
                g: boolean,
                h: Readonly<{
                    boom: string
                }>
            }>
        }>
    }>
}> = {
        b: 33,
        c: [78, 99],
        d:{e:{f:{g:true, h:{boom:'selecta'}}}}
}

a.d.e.f.h.boom = 'respek'; // error: Cannot assign to 'boom' because it is a constant or a read-only property.

显然，这是一个同义反复的语句，所以我建议你为你的对象定义合适的类结构。你并没有真正利用Typescript的任何特性，只是声明了一个嵌套的，无类型的对象。
但是如果你真的需要不使用类型定义，我认为唯一的方法是像Hampus建议的那样定义一个冷冻库（喜欢这个术语：D）。摘自MDN的deepFreeze(obj)函数：

function freezer(obj) {
    Object.getOwnPropertyNames(obj).forEach(name => {
        if (typeof obj[name] == 'object' && obj[name] !== null)
            freezer(obj[name]);
    });
    return Object.freeze(obj);
}

const a = freezer({
    b:33, 
    c:[78, 99], 
    d:{e:{f:{g:true, h:{boom:'selecta'}}}}});

a.d.e.f.h.boom='respek'; // this does NOT throw an error. it simply does not override the value.

tl;dr：如果不定义类型，你就不能得到编译器类型错误。这就是Typescript的全部意义。
编辑：
这最后一个陈述是错误的。例如，

let a = 1
a = "hello"

将抛出一个错误，因为类型被隐式设置为number。然而，对于readonly，我认为，你需要像上面定义的那样正确声明。

Minko Gechev创建了DeepReadonly类型：

type DeepReadonly<T> =
  T extends (infer R)[] ? DeepReadonlyArray<R> :
  T extends Function ? T :
  T extends object ? DeepReadonlyObject<T> :
  T;

interface DeepReadonlyArray<T> extends ReadonlyArray<DeepReadonly<T>> {}

type DeepReadonlyObject<T> = {
  readonly [P in keyof T]: DeepReadonly<T[P]>;
};

interface Person {
  name: string;
  job: { company: string, position:string };
}

const person: DeepReadonly<Person> = {
  name: 'Minko',
  job: {
    company: 'Google',
    position: 'Software engineer'
  }
};

person.job.company = 'Alphabet'; // Error

其他OOP语言默认具有类不变性，TypeScript也不例外。您可以使用经典的OO方式，如Java或PHP：

export class ClassicImmutableObject {
    private readonly _stringProperty: string;
    private readonly _numberProperty: number;

    constructor(stringProperty: string, numberProperty: number) {
        this._stringProperty = stringProperty;
        this._numberProperty = numberProperty;
    }
    
    get stringProperty(): string {
        return this._stringProperty;
    }

    get numberProperty(): number {
        return this._numberProperty;
    }

    withStringProperty(stringProperty: string): ClassicImmutableObject {
        return new ClassicImmutableObject(stringProperty, this._numberProperty);
    }

    withNumberProperty(numberProperty: number): ClassicImmutableObject {
        return new ClassicImmutableObject(this._stringProperty, numberProperty);
    }
}

你可以在代码中使用它：

import { ClassicImmutableObject } from './classic-immutable-object';

//...
immutableObjectExperiment(): string {
    const immutableObject: ClassicImmutableObject = 
        new ClassicImmutableObject('test string', 123);

    // this is not allowed: (TS2540 Can not assign to read-only property)
    //immutableObject.stringProperty = 'modified';

    let result = `Original classic immutable object: ${JSON.stringify(immutableObject)} \r\n`;
    result += 'This demonstrates how to use getters:\r\n';
    result += `stringProperty value: ${immutableObject.stringProperty}\r\n`;
    result += `numberProperty value: ${immutableObject.numberProperty}\r\n\r\n`;

    const modifiedImmutableObject: ClassicImmutableObject =
      immutableObject.withStringProperty('modified test string');

    result += `Modified classic immutable object with only stringProperty changed: ${JSON.stringify(modifiedImmutableObject)}\r\n`;
    result += `Original immutable object is still available and unchanged: ${JSON.stringify(immutableObject)}`;

    return result;
}

此函数的结果应为：

Original classic immutable object: {"_stringProperty":"test string","_numberProperty":123}
This demonstrates how to use getters:
stringProperty value: test string
numberProperty value: 123

Modified classic immutable object with only stringProperty changed: {"_stringProperty":"modified test string","_numberProperty":123}
Original immutable object is still available and unchanged: {"_stringProperty":"test string","_numberProperty":123}

查看https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/freeze或https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/defineProperty
冻结可能会做你想要的，但至少WebStorm不会警告你，当试图编辑对象和Chrome失败无声。

const obj = { val: 1 }; 
Object.freeze(obj);
obj.val = 2;

console.log(obj);
-> { val: 1 }

不能在冻结对象的属性集中添加或删除任何内容。任何这样做的尝试都将失败，可能是静默失败，也可能是抛出TypeError异常

这是可行的：

const a= new class {
    readonly b = 33, 
    readonly c:ReadonlyArray<number> = [78, 99], 
    readonly d = new class {
        readonly e = new class {
            readonly f = new class {
                readonly g:true, 
                readonly h: new class {
                    readonly boom:'selecta'}}}};