TypeScript Object is possibly undefined

   .
   .
   .
   
   newHzl[hanzi].pinyin = newHzl[hanzi].pinyin.filter(eachPinyin => pinyinEnglish[eachPinyin]);
} // for loop   

That yields this error:

error: TS2532 [ERROR]: Object is possibly 'undefined'.
        newHzl[hanzi].pinyin = newHzl[hanzi].pinyin.filter(

Got a similar error code on following code, and removed the error by checking if a variable has nothing, if nothing then skip(continue)

for (const [hanzi, { pinyinEnglish }] of Object.entries(hzl)) {
    if (!pinyinEnglish) {
        continue;
    }
    
    for (const pinyin of Object.keys(pinyinEnglish)) {
        if (pinyinEnglish[pinyin].length === 0) {
            delete pinyinEnglish[pinyin];
        }
    }
    
    .
    .
    .    

I tried to do the same solution on the post's first code, but it still yields a compile error of Object is possibly 'undefined'

	.
    .
    .
    
    if (!newHzl[hanzi].pinyin) {
        continue;
    }

    newHzl[hanzi].pinyin = newHzl[hanzi].pinyin.filter(eachPinyin => pinyinEnglish[eachPinyin]);
} // for loop    

The workaround is to introduce a variable so the compiler will not have a hard time inferring the code's control flow:

    .
    .
    .

    const hanziPinyin = newHzl[hanzi].pinyin;
    if (!hanziPinyin) {
        continue;
    }

    newHzl[hanzi].pinyin = hanziPinyin.filter(eachPinyin => pinyinEnglish[eachPinyin]);
} // for loop   

The problem went away