I am trying to get the following background prop set to a image in my src/images/bird.jpg directory. Here is my code, but I get a Cannot read property 'id' of undefined from my graphQl query in the console and the background prop returns null in React Inspector, What am I doing wrong?
/src/pages/index.js
import React from 'react'
import { graphql } from 'gatsby'
import Img from 'gatsby-image'
import Layout from '../components/layout'
const IndexPage = ({ data }) => (
<Layout>
<h1>Hi people</h1>
<p>{data.site.siteMetadata.title}</p>
<p>{data.site.siteMetadata.desc}</p>
<p>Welcome to your new Gatsby site.</p>
<p>Now go build something great.</p>
</Layout>
)
export default IndexPage
export const query = graphql`
query SiteMeta {
site {
siteMetadata {
title
desc
}
}
background: imageSharp(id: { regex: "/bird.jpg/" }) {
sizes(maxWidth: 1240) {
...GatsbyImageSharpSizes
}
}
}
`
Related
There have been a couple of similar questions, but none helped me really understand using a GraphQL inside a (class) component other than the ones in the pages folder.
My project structure looks like that:
-src
--components
---aboutBody
----index.js
--pages
---about.js
I have a page component called about (Prismic single page type) and set up some components to "fill" this page (cleaned up for better readability).
class AboutPage extends Component {
render() {
return (
<LayoutDefault>
<AboutBody
introHeadline={this.props.data.prismicAbout.data.intro_headline.text}
introParagraph={this.props.data.prismicAbout.data.intro_paragraph.text}
/>
</LayoutDefault>
)
}
}
export default AboutPage
This is what my query looks like (had it like this in both files):
export const aboutQuery = graphql`
query About {
prismicAbout {
data {
# Intro Block
intro_headline {
text
}
intro_paragraph {
text
}
}
}
}
`
(In case I am missing a bracket at the bottom, it's due to cleaning up the query example for SO — as mentioned earlier, it's working in my page component).
My graphql query is at the bottom of the AboutPage page component. It works like a charm and as intended.
But to clean this page up a bit I wanted to create appropriate components and put my query inside each component (e.g. aboutBody, aboutCarousel), again cleaned up a bit:
class AboutBody extends Component {
render() {
return (
<StyledIntro>
<h3>About</h3>
<h1>{this.props.data.prismicAbout.data.intro_headline.text}</h1>
</StyledIntro>
)
}
}
export default AboutBody
And I deleted the query from my about page component and put it inside my AboutBody component (exactly the way as shown above).
But with this it always returns the error Cannot read property 'prismicAbout' of undefined (I can't even console log the data, it always returns the same error).
I used import { graphql } from "gatsby" in both files.
Long story short, how can I achieve putting a query inside my class component and render only the component without clarifying the props in my page component like this:
class AboutPage extends Component {
render() {
return (
<LayoutDefault>
<AboutBody />
</LayoutDefault>
)
}
}
Some blogs posts mention GraphQL Query Fragments, but not sure if this is the correct use case or if it's simply a stupid beginner mistake...
That's because you can't use graphql like this in your component.
To use graphql in a component, you've got two options : useStaticQuery function or StaticQuery component, both from graphql
for useStaticQuery :
import React from "react"
import { useStaticQuery, graphql } from "gatsby"
const MyElement = () => {
const data = useStaticQuery(graphql`
query About {
prismicAbout {
data {
intro_headline {
text
}
intro_paragraph {
text
}
}
}
}
`)
return (
<StyledIntro>
<h3>About</h3>
<h1>{this.props.data.prismicAbout.data.intro_headline.text}</h1>
</StyledIntro>
)
}
export default MyElement
with staticQuery
import React from 'react'
import { StaticQuery, graphql } from 'gatsby';
const MyElement = () => {
return(
<StaticQuery
query About {
prismicAbout {
data {
intro_headline {
text
}
intro_paragraph {
text
}
}
}
}
`}
render={data => (
<StyledIntro>
<h3>About</h3>
<h1>{this.props.data.prismicAbout.data.intro_headline.text}</h1>
</StyledIntro>
)}
/>
)
}
export default MyElement
Hope that helps you!
You can only use a query like that in a page component. One option would be to just query it in the page and then pass the data in to your component as a prop. Another is to use a static query in the component.
If your query has variables in it then you can't use a static query. In that case you should either query it all in the page and then pass it in, or you can put the part of the query related to that component in a fragment within that component's file and then use that fragment in the page query.
Example of using fragments in a component and then passing the data into the component:
// MyComponent.js
import React from "react"
import { graphql } from 'gatsby'
const MyComponent = (props) => {
const { myProp: { someData } } = props
return (
<div>
my awesome component
</div>
)
}
export default MyComponent
export const query = graphql`
fragment MyAwesomeFragment on Site {
someData {
item
}
}
`
// MyPage.js
import React from "react"
import { graphql } from "gatsby"
import MyComponent from "../components/MyComponent"
export default ({ data }) => {
return (
<div>
{/*
You can pass all the data from the fragment
back to the component that defined it
*/}
<MyComponent myProp={data.site.someData} />
</div>
)
}
export const query = graphql`
query {
site {
...MyAwesomeFragment
}
}
`
Read more about using fragments in Gatsby docs.
If you need to render the query in a class based component. This worked for me:
import React, { Component } from 'react';
import { StaticQuery, graphql } from 'gatsby';
class Layout extends Component {
render() {
return (
<StaticQuery
query={graphql`
query SiteTitleQuery {
site {
siteMetadata {
title
}
}
}
`}
render={data => {
return (
<main>
{!data && <p>Loading...</p>}
{data && data.site.siteMetadata.title}
</main>
)
}}
/>
);
}
}
I'm able to get the image data in GraphiQL but can't get to work in the component. Please let me know where I'm going wrong.
import React from "react";
import { graphql } from "gatsby";
import Img from "gatsby-image"
export default function Landing({ data }) {
console.log(data) // undefined
return (
<section id="landing" className="d-flex flex-column justify-content-around">
</section >
)
}
export const query = graphql`
{
img: file(relativePath: {eq: "landing-women.jpg"}){
childImageSharp{
fluid{
src
}
}
}
}
`;
I think it has to do with your component not being in the 'pages' folder and so not being a page. Is that correct? Using page queries in components will cause the data to be undefined.
In gatsby you have page queries (for pages), and static queries (for components)
Usually, you would have a uniquely named query on each page component, otherwise I'm not sure whether Gatsby knows to extract it and pass it's resolved value as the data prop or not.
import React from "react";
import { graphql } from "gatsby";
import Img from "gatsby-image"
export default function Landing({ data }) {
console.log(data)
return (
<section id="landing" className="d-flex flex-column justify-content-around">
</section >
)
}
export const query = graphql`
query LandingQuery {
img: file(relativePath: {eq: "landing-women.jpg"}){
childImageSharp{
fluid{
src
}
}
}
}
`;
Well I don't know the exact reason behind it but, I did solve the issue by creating a seperate component for the image query and then importing it where required.
import React from "react";
import { useStaticQuery, graphql } from "gatsby"
import Img from "gatsby-image";
const Image = () => {
const data = useStaticQuery(graphql`
query {
img: file(relativePath: {eq: "landing-women.jpg"}){
childImageSharp{
fluid{
...GatsbyImageSharpFluid_tracedSVG
}
}
}
}
`)
return <Img className="img-fluid order-0 order-md-1 col-12 col-md-7"
fluid= {data.img.childImageSharp.fluid} />
}
export default Image
First time posting here, but I've been struggling with this for a few days now.
Basically I have a graphQL query that pulls in product data from contentful and then display it on a GatsbyJS page. The query correctly displays for the title, price, and description of the product but it wont load in the image. Unfortunately I keep receiving errors such as:
"TypeError: Cannot read property '0' of undefined"
or
Cannot read property 'src' of undefined. (When changing the query to look at the src of an image. When I do this method, the url does have a value according to GraphiQL)
here's the code for the page I am currently working on:
import React from 'react'
import { graphql } from 'gatsby'
import Img from 'gatsby-image'
import Layout from '../components/Layout'
import './shop.scss'
const Shop = ({ data }) => {
return (
<Layout>
<section>
{data.allContentfulProducts.edges.map( ({ node }) => (
<article key={node.id}>
<Img
fluid={node.images.fluid}
/>
<p>{node.productName}</p>
</article>
))}
</section>
</Layout>
)
}
export const productQuery = graphql`
query {
allContentfulProducts {
edges {
node {
id
productName
images {
fluid {
...GatsbyContentfulFluid
}
}
}
}
}
}
`
export default Shop
I think there is a problem with you graphQL Query. Try this one:
export const productQuery = graphql`
query {
allContentfulProducts {
edges {
node {
id
productName
image {
fluid {
src
...GatsbyContentfulFluid
}
}
}
}
}
}
`
If this query is not helping please show us the structure of your contentful assets.
There have been a couple of similar questions, but none helped me really understand using a GraphQL inside a (class) component other than the ones in the pages folder.
My project structure looks like that:
-src
--components
---aboutBody
----index.js
--pages
---about.js
I have a page component called about (Prismic single page type) and set up some components to "fill" this page (cleaned up for better readability).
class AboutPage extends Component {
render() {
return (
<LayoutDefault>
<AboutBody
introHeadline={this.props.data.prismicAbout.data.intro_headline.text}
introParagraph={this.props.data.prismicAbout.data.intro_paragraph.text}
/>
</LayoutDefault>
)
}
}
export default AboutPage
This is what my query looks like (had it like this in both files):
export const aboutQuery = graphql`
query About {
prismicAbout {
data {
# Intro Block
intro_headline {
text
}
intro_paragraph {
text
}
}
}
}
`
(In case I am missing a bracket at the bottom, it's due to cleaning up the query example for SO — as mentioned earlier, it's working in my page component).
My graphql query is at the bottom of the AboutPage page component. It works like a charm and as intended.
But to clean this page up a bit I wanted to create appropriate components and put my query inside each component (e.g. aboutBody, aboutCarousel), again cleaned up a bit:
class AboutBody extends Component {
render() {
return (
<StyledIntro>
<h3>About</h3>
<h1>{this.props.data.prismicAbout.data.intro_headline.text}</h1>
</StyledIntro>
)
}
}
export default AboutBody
And I deleted the query from my about page component and put it inside my AboutBody component (exactly the way as shown above).
But with this it always returns the error Cannot read property 'prismicAbout' of undefined (I can't even console log the data, it always returns the same error).
I used import { graphql } from "gatsby" in both files.
Long story short, how can I achieve putting a query inside my class component and render only the component without clarifying the props in my page component like this:
class AboutPage extends Component {
render() {
return (
<LayoutDefault>
<AboutBody />
</LayoutDefault>
)
}
}
Some blogs posts mention GraphQL Query Fragments, but not sure if this is the correct use case or if it's simply a stupid beginner mistake...
That's because you can't use graphql like this in your component.
To use graphql in a component, you've got two options : useStaticQuery function or StaticQuery component, both from graphql
for useStaticQuery :
import React from "react"
import { useStaticQuery, graphql } from "gatsby"
const MyElement = () => {
const data = useStaticQuery(graphql`
query About {
prismicAbout {
data {
intro_headline {
text
}
intro_paragraph {
text
}
}
}
}
`)
return (
<StyledIntro>
<h3>About</h3>
<h1>{this.props.data.prismicAbout.data.intro_headline.text}</h1>
</StyledIntro>
)
}
export default MyElement
with staticQuery
import React from 'react'
import { StaticQuery, graphql } from 'gatsby';
const MyElement = () => {
return(
<StaticQuery
query About {
prismicAbout {
data {
intro_headline {
text
}
intro_paragraph {
text
}
}
}
}
`}
render={data => (
<StyledIntro>
<h3>About</h3>
<h1>{this.props.data.prismicAbout.data.intro_headline.text}</h1>
</StyledIntro>
)}
/>
)
}
export default MyElement
Hope that helps you!
You can only use a query like that in a page component. One option would be to just query it in the page and then pass the data in to your component as a prop. Another is to use a static query in the component.
If your query has variables in it then you can't use a static query. In that case you should either query it all in the page and then pass it in, or you can put the part of the query related to that component in a fragment within that component's file and then use that fragment in the page query.
Example of using fragments in a component and then passing the data into the component:
// MyComponent.js
import React from "react"
import { graphql } from 'gatsby'
const MyComponent = (props) => {
const { myProp: { someData } } = props
return (
<div>
my awesome component
</div>
)
}
export default MyComponent
export const query = graphql`
fragment MyAwesomeFragment on Site {
someData {
item
}
}
`
// MyPage.js
import React from "react"
import { graphql } from "gatsby"
import MyComponent from "../components/MyComponent"
export default ({ data }) => {
return (
<div>
{/*
You can pass all the data from the fragment
back to the component that defined it
*/}
<MyComponent myProp={data.site.someData} />
</div>
)
}
export const query = graphql`
query {
site {
...MyAwesomeFragment
}
}
`
Read more about using fragments in Gatsby docs.
If you need to render the query in a class based component. This worked for me:
import React, { Component } from 'react';
import { StaticQuery, graphql } from 'gatsby';
class Layout extends Component {
render() {
return (
<StaticQuery
query={graphql`
query SiteTitleQuery {
site {
siteMetadata {
title
}
}
}
`}
render={data => {
return (
<main>
{!data && <p>Loading...</p>}
{data && data.site.siteMetadata.title}
</main>
)
}}
/>
);
}
}
I am pulling in data from Contentful api into gatsby and all seems to be tracing out fine. However when I implement the component that pulls in the contentful data on to my index.js file I keep getting an undefined error.
WebpackError: Cannot read property 'allContentfulProduct' of undefined
Product.js:
import React from "react"
const Product = ({data}) => {
const assets = data.allContentfulProduct.edges[0].node
const { productName } = assets;
return (
<div>
{productName}
</div>
)
};
export default Product;
export const pageQuery = graphql`
query ImageAPIExamples {
allContentfulProduct {
edges {
node {
id
productName
}
}
}
}
`
Index.JS
import React from 'react';
import Products from '../components/products/image';
const IndexPage = props =>
(<main>
Hello
</main>);
export default IndexPage;
So it looks like I was able to solve this by passing props and querying the data on the index.js page.
Solution:
Index.js:
import React from 'react';
import Products from '../components/products/image';
const IndexPage = props =>
(<main>
<Products data={props.data.allContentfulProduct.edges[0].node} />
</main>);
export default IndexPage;
export const pageQuery = graphql`
query IndexQuery {
allContentfulProduct {
edges {
node {
id
productName
image {
file{
url
}
}
}
}
}
}
`;