Node.js中Fetch不执行await等待的问题排查求助

我尝试让Node.js等待fetch请求的成功或失败结果，已知fetch会返回Promise且已配置对应处理逻辑，但await未按预期生效，具体尝试的写法及问题如下：

第一种写法：带then/catch的await #

实际执行时，函数直接返回调用方，既不打印@@ after fetch fetchResult=，也不执行成功/失败回调，甚至未发起指定的POST请求。

async function getAccessToken() {
        ...
        let fetchResult = await fetch(argumentParserResult.authorizationUrl, {
            method: 'POST',
            body: formData,
            headers: headers

        }).then(success => {
            console.log("Success reached. " + JSON.stringify(success));
            process.exit(2);
        }, other => {
            console.log("Other reached. " + JSON.stringify(other));
            process.exit(3);
        });
        console.log('@@ after fetch fetchResult=' + fetchResult);
        ...
}

第二种写法：try/catch包裹await #

日志仅输出到@@getAccessToken BP7，未触发finally块、错误处理逻辑或fetch后的日志内容。

async function getAccessToken() {
    console.log('@@getAccessToken BP1');
    if (argumentParserResult.authenticationScheme == 'OAUTH2') {
        console.log('@@getAccessToken BP2');
        const fetch = require('node-fetch');
        const url = argumentParserResult.resourceUrl;
        console.log('@@getAccessToken BP3');
        let formData = new URLSearchParams({
            'grant_type': 'client_credentials',
            'client_id': argumentParserResult.clientId,
            'scope': argumentParserResult.clientScope,
            'client_secret': argumentParserResult.clientSecret
        })
        console.log('@@getAccessToken BP4');

        let headers = {
            'Content-Type': 'application/x-www-form-urlencoded'
        };
        console.log('@@getAccessToken BP5');


        console.log('POST ' + argumentParserResult.authorizationUrl);
        console.log(JSON.stringify(formData));
        console.log('@@getAccessToken BP6');
        try {
            console.log('@@getAccessToken BP7');
            const response = await fetch(argumentParserResult.authorizationUrl, {
                method: 'POST',
                body: formData,
                headers,
            });
            console.log('@@getAccessToken BP8');
            console.log(`Success reached.`, JSON.stringify(response));
            const json = await response.json();
            console.log('@@getAccessToken BP9');
            console.log(`Other reached.`, json);
            return json;
        } catch (error) {
            console.log('@@getAccessToken BP10');
            console.log(`!! something went wrong`, error.message);
            console.error(error);
            return error;
        } finally {
            console.log('@@getAccessToken BP11');
            console.log(`fetch finished`);
        }
        console.log('@@getAccessToken BP12');

    }
    console.log('@@getAccessToken BP13');
    return "Should not have reached this point";

}

第三种写法：带返回值的then链+await #

日志仅输出到POST请求信息，之后直接返回调用方，无任何fetch请求执行的迹象。

async function getAccessToken() {
    console.log('@@getAccessToken BP1');
    if (argumentParserResult.authenticationScheme == 'OAUTH2') {
        console.log('@@getAccessToken BP2');
        const fetch = require('node-fetch');
        const url = argumentParserResult.resourceUrl;
        console.log('@@BP1.9');
        let formData = new URLSearchParams({
            'grant_type': 'client_credentials',
            'client_id': argumentParserResult.clientId,
            'scope': argumentParserResult.clientScope,
            'client_secret': argumentParserResult.clientSecret
        })
        console.log('@@getAccessToken BP3');

        let headers = {
            'Content-Type': 'application/x-www-form-urlencoded'
        };
        console.log('@@getAccessToken BP4');


        console.log('POST ' + argumentParserResult.authorizationUrl);
        console.log(JSON.stringify(formData));
        let response = await fetch(argumentParserResult.authorizationUrl, {
            method: 'POST',
            body: formData,
            headers: headers

        }).then(success => {
            console.log('@@getAccessToken BP5');
            console.log("Success reached. " + JSON.stringify(success));
            return success // !--> LOOK HERE, you should return the success variable
        }).catch(e => {
            console.log('@@getAccessToken BP6');
            console.log(e) // !--> LOOK HERE, if you catch the error, no error will be thrown to the caller
            return e
        });
        console.log('@@getAccessToken BP7');
        console.log('@@ after fetch fetchResult=', fetchResult); // !--> LOOK HERE, this log will always log something now, it could be the responso or the error       

    }
    console.log('@@getAccessToken BP8');
}

请问为何await完全不生效，且fetch请求始终未执行？

内容的提问来源于stack exchange，提问作者Woodsman