实现

2024年02月05日

柏拉文

越努力，越幸运

一、实现

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function JSONStringify(data) {
    const isCycle = (obj) => {
        const weakSet = new WeakSet();
        let detected = false;
        const detect = (obj) => {
            if (obj != null && typeof obj !== "object") {
                return;
            }
            if (weakSet.has(obj)) {
                detected = true;
                return detected;
            }
            weakSet.add(obj);
            for (let key in obj) {
                if (obj.hasOwnProperty(key)) {
                    detect(obj[key]);
                }
            }
        };
        detect(obj);
        return detected;
    };
    if (isCycle(data)) {
        throw new TypeError("Converting circular structure to JSON");
    }
    if (typeof data === "bigint") {
        throw new TypeError("BigInt value can't be serialized in JSON");
    }
    const type = typeof data;
    const commonKeys = ["undefined", "function", "symbol"];
    const getType = (s) => {
        return Object.prototype.toString
        .call(s)
        .replace(/\[object (.*?)\]/)
        .toLowerCase();
    };
    if (type !== "object" || data === null) {
        let result = data;
        if ([NaN, Infinity, null].includes(data)) {
            result = null;
        } else if (commonKeys.includes(type)) {
            return undefined;
        } else if (type === "string") {
            result = `"${data}"`;
        }
        return String(result);
    } else if (type === "object") {
        if (typeof data.toJSON === "function") {
            return JSONStringify(data.toJSON());
        } else if (Array.isArray(data)) {
            let result = data.map((it) => {
                return commonKeys.includes(typeof it)
                ? "null"
                : JSONStringify(it);
            });
            return `[${result}]`.replace(/'/g, '"');
        } else {
        if (["boolean", "number"].includes(getType(data))) {
            return String(data);
        } else if (getType(data) === "string") {
            return `"${data}"`;
        } else {
            let result = [];
            Object.keys(data).forEach((key) => {
                if (typeof key !== "symbol") {
                    const value = data[key];
                    if (!commonKeys.includes(typeof value)) {
                        result.push(`"${key}":${JSONStringify(value)}`);
                    }
                }
            });
            return `{${result}}`.replace(/'/g, '"');
        }
        }
    }
}

const obj = {
    name: "like",
    age: 23,
    like: {
        ball: [1, 2, 3],
    },
};

const result = JSONStringify(obj);
console.log(result)

二、测试

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