NodeJS无法读取未定义的属性“ push”

问题描述

我有一个函数在页面上抓取一些数据，并将其存储在变量“结果”中。有几页，因此该函数包含在“ for”循环中。

const PageScraping = async(page,query) =>{
await page.goto(query,{ waitUntil: "networkidle2" });

const result = await page.evaluate(() =>{
        return(
            [...document.querySelectorAll('.card--result__body')].map((o) => ({
                type:
                    o.querySelector('.card__title-link') &&
                    o.querySelector('.card__title-link').innerText,price:
                    o.querySelector('.card--result__price > span > .sr-only') &&
                    parseInt(o.querySelector('.card--result__price > span > .sr-only').innerText.replace('€','')),rooms:
                    o.querySelector('.card__@R_50_404[email protected]__@R_50_4045@ions > .card__@R_50_404[email protected]__@R_50_404[email protected]__@R_50_4045@ion--property > .abbreviation > .sr-only') &&
                    parseInt(o.querySelector('.card__@R_50_404[email protected]__@R_50_4045@ions > .card__@R_50_404[email protected]__@R_50_404[email protected]__@R_50_4045@ion--property > .abbreviation > .sr-only').innerText.replace(' chambres',surface:
                    o.querySelector('.card__@R_50_404[email protected]__@R_50_404[email protected]__@R_50_4045@ion--property') &&
                    parseInt(o.querySelector('.card__@R_50_404[email protected]__@R_50_404[email protected]__@R_50_4045@ion--property').innerText.split(' ')[4]),postcode:
                    o.querySelector('.card__@R_50_404[email protected]__@R_50_404[email protected]__@R_50_4045@ion--locality') &&
                    o.querySelector('.card__@R_50_404[email protected]__@R_50_404[email protected]__@R_50_4045@ion--locality').innerText.split(' ')[0],url:
                    o.querySelector('.card__title.card--result__title > a') &&
                    o.querySelector('.card__title.card--result__title > a').href,}))
            );
        });
return result;

}

之后，我需要将结果存储在另一个包含所有数据的变量中（循环）。在那里，我正在使用“ push”，但出现错误：

无法读取未定义的属性“ push”

    let all_results;
    try{
       let query = 'myurl'
       await page.goto(query,{ waitUntil: "networkidle2" });
       let max_pages = parseInt(await page.$eval('.pagination > li:nth-last-child(2) > a > .button__label',o => o.innerText));
       for(let i = 1; i < max_pages+1; i++){
           console.log('page ',i,' of ',max_pages);
           try{
               const result = await PageScraping(page,query);
               query = `urlpage${i+1}`;
               all_results.push(result);
               console.log(all_results);

            } catch(e){
               console.log('ERROR: Could not reach landing page',e.message);
           }
       }

   } catch(error) {
       console.log('ERROR: Could not reach landing page',error.message);

   } finally {
       try{
           await browser.close();
        }catch(browser_error){
            console.log('ERROR cant close browser??',browser_error.message)
        }
    }
}

解决方法

以下代码正在运行。按照建议，我将“ all_results”声明为数组。

    let all_results = [];
    try{
       let query = 'myurl'
       await page.goto(query,{ waitUntil: "networkidle2" });
       let max_pages = parseInt(await page.$eval('.pagination > li:nth-last-child(2) > a > .button__label',o => o.innerText));
       for(let i = 1; i < max_pages+1; i++){
           console.log('page ',i,' of ',max_pages);
           try{
               const result = await PageScraping(page,query);
               query = `urlpage${i+1}`;
               all_results.push(result);
               console.log(all_results);

            } catch(e){
               console.log('ERROR: could not reach landing page',e.message);
           }
       }

   } catch(error) {
       console.log('ERROR: could not reach landing page',error.message);

   } finally {
       try{
           await browser.close();
        }catch(browser_error){
            console.log('ERROR cant close browser??',browser_error.message)
        }
    }
}