Filter

{
  allMarkdownRemark(filter: { frontmatter: { title: { ne: "" } } }) {
    totalCount
    edges {
      node {
        frontmatter {
          title
        }
      }
    }
  }
}

In this query filter and the ne (not equals) operator is used to show only results that have a title. You can find a good video tutorial on this here.

Gatsby relies on Sift to enable MongoDB-like query syntax for object filtering. This allows Gatsby to support operators like eq, ne, in, regex and querying nested fields through the __ connector.

It is also possible to filter on multiple fields - just separate the individual filters by a comma (works as an AND):

filter: { contentType: { in: ["post", "page"] }, draft: { eq: false } }

Complete list of possible operators

• eq: short for equal, must match the given data exactly
• ne: short for not equal, must be different from the given data
• regex: short for regular expression, must match the given pattern. Note that backslashes need to be escaped twice, so /\w+/ needs to be written as "/\\\\w+/".
• glob: short for global, allows to use wildcard * which acts as a placeholder for any non-empty string
• in: short for in array, must be an element of the array
• nin: short for not in array, must NOT be an element of the array
• gt: short for greater than, must be greater than given value
• gte: short for greater than or equal, must be greater than or equal to given value
• lt: short for less than, must be less than given value
• lte: short for less than or equal, must be less than or equal to given value
• elemMatch: short for element match, this indicates that the field you are filtering will return an array of elements, on which you can apply a filter using the previous operators

If you want to understand more how these filters work, looking at the corresponding tests in the codebase could be very useful.