I want to filter some posts from data.I try to use this code but it don't work.It run out post.frontmatter.title.filter is not a function

{posts.map((post, index) => (
 post.frontmatter.title.filter(name=>name.includes('J')).map(filterdtitle=>(
<li>{filterdtitle}</li>
))
))}

I get the data of posts by getStaticProps like this and then I pass the posts to the function.The posts include title.I can get by {post.frontmatter.title},it is working.

 const { data: frontmatter } = matter(markdownWithMeta)

    return {
      slug,
      frontmatter
    }
  })

I want to know that how make it work.Thank you

CodePudding user response：

Looks like title is a string. filter() and includes() methods are available only for array.

CodePudding user response：

I believe you need to rewrite your code like this.

1. the title is a string, and the filter doesn't support string

2. you added an extra step by using a filter and include in the same line for a title.

{
  posts.map((post, index) =>
    post.frontmatter
      .filter((name) => title.includes("J"))
      .map((filterdtitle) => <li>{filterdtitle}</li>)
  );
}