尝试在 React 中使用 map 子对象时出现未定义错误

Question

I'm trying to get image url for nested JSON object.

Tried {post.image.url} but I get an error saying url undefined

I appreciate any help or guidance that could be offered. New to Javascript / React but after an hour of Googling and searching couldn't come up with a solution for this. Must be missing something simple:-P

Here's my code...

export const getAllPosts = async () => {
    return await fetch(
        `https://notion-api.splitbee.io/v1/table/${NOTION_BLOG_ID}`
    ).then((res) => res.json());
}
export async function getStaticProps() {
    const posts = await getAllPosts()
    return {
        props: {
            posts
        },
    };
}
function Blog({ posts }) {
    return (
        <div>
            {posts.map((post) => (
                <Link href="/blog/[slug]" as={`/blog/${post.slug}`}>
                    <div>
                        <div className='text-6xl'>{post.title}</div>
                        <img className='w-24' src={post.imgUrl}></img>

                        
                        {/*{post.image.rawUrl}*/}

                    </div>
                </Link>
            ))}
        </div>
    );
}
export default Blog

Here's the JSON...

[
{
"id": "90ee0723-aeb5-4d64-a970-332aa8f819f6",
"slug": "first-post",
"date": "2020-04-21",
"Related to Notion API Worker (Column)": [
"0976bfa6-392a-40b0-8415-94a006dba8d9"
],
"imgUrl": "https://www.notion.so/image/https:%2F%2Fs3-us-west-2.amazonaws.com%2Fsecure.notion-static.com%2F689883de-2434-4be3-8179-a8ba62a7bc1e%2Fsnowmountain.jpg?table=block&id=90ee0723-aeb5-4d64-a970-332aa8f819f6&cache=v2",
"image": [
{
"name": "snowmountain.jpg",
"url": "https://www.notion.so/image/https:%2F%2Fs3-us-west-2.amazonaws.com%2Fsecure.notion-static.com%2F689883de-2434-4be3-8179-a8ba62a7bc1e%2Fsnowmountain.jpg?table=block&id=90ee0723-aeb5-4d64-a970-332aa8f819f6&cache=v2",
"rawUrl": "https://s3-us-west-2.amazonaws.com/secure.notion-static.com/689883de-2434-4be3-8179-a8ba62a7bc1e/snowmountain.jpg"
}
],
"title": "My first blogpost bruce"
}
]

Answer 1

There is no need to call then() method, if you use async\await .

As mdn says:

await can be put in front of any async promise-based function to pause your code on that line until the promise fulfills, then return the resulting value.

export const getAllPosts = async () => {
    return await fetch(
        `https://notion-api.splitbee.io/v1/table/${NOTION_BLOG_ID}`
    );
}

export async function getStaticProps() {
    const posts = await getAllPosts()
    return {
        props: {
            posts
        },
    };
}

Answer 2

The image property of a post is an array as denoted by the bracket on the end of line 1:

1. "image": [
2.   {
3.     "name": "snowmountain.jpg",
4.     "url": "https://www.notion.so/image/https:%2F%2Fs3-us-west-2.amazonaws.com%2Fsecure.notion-static.com%2F689883de-2434-4be3-8179-a8ba62a7bc1e%2Fsnowmountain.jpg?table=block&id=90ee0723-aeb5-4d64-a970-332aa8f819f6&cache=v2",
5.     "rawUrl": "https://s3-us-west-2.amazonaws.com/secure.notion-static.com/689883de-2434-4be3-8179-a8ba62a7bc1e/snowmountain.jpg"
6.   }
7. ],

If you know that there will always be exactly one image you could access it directly by referencing the first array item.

function Blog({ posts }) {
    return (
        <div>
            {posts.map((post) => (
                <Link href="/blog/[slug]" as={`/blog/${post.slug}`}>
                    <div>
                        <div className='text-6xl'>{post.title}</div>
                        <img className='w-24' src={post.imgUrl}></img>

                        
                        {post.image && post.image[0].rawUrl}

                    </div>
                </Link>
            ))}
        </div>
    );
}

Note that this could err if the array is undefined / null or if it's empty, so you should probably safe-guard it by only displaying something if it exists.