fix(gatsby-plugin-image): Better propType handling for StaticImage (#28606)

* fix(gatsby-plugin-image): Better propType handling for StaticImage

* Normalise props

* Handle tracedSVG not being camel case

Author: ascorbic

e2e-tests/gatsby-static-image/src/pages/fluid.js

@@ -9,6 +9,7 @@ const FluidPage = () => (
       <StaticImage
         src="../images/citrus-fruits.jpg"
         layout="fluid"
+        maxWidth={700}
         alt="Citrus fruits"
       />
     </div>

packages/gatsby-plugin-image/package.json

@@ -84,6 +84,7 @@
     "@babel/traverse": "^7.12.5",
     "babel-jsx-utils": "^1.0.1",
     "babel-plugin-remove-graphql-queries": "^2.14.0-next.0",
+    "camelcase": "^5.3.1",
     "chokidar": "^3.4.3",
     "fs-extra": "^8.1.0",
     "gatsby-core-utils": "^1.8.0-next.0",

packages/gatsby-plugin-image/src/__tests__/babel-utils.ts

@@ -0,0 +1,42 @@
+import { normalizeProps } from "../babel-helpers"
+
+describe(`static-image babel parser`, () => {
+  it(`normalises props`, () => {
+    const input = {
+      formats: [`webP`, `JPG`, `png`],
+      placeholder: `DOMINANT_COLOR`,
+      layout: `FLUID`,
+    }
+    expect(normalizeProps(input)).toEqual({
+      formats: [`webp`, `jpg`, `png`],
+      layout: `fluid`,
+      placeholder: `dominantColor`,
+    })
+  })
+
+  it(`handles tracedSvg`, () => {
+    expect(
+      normalizeProps({
+        placeholder: `TRACED_SVG`,
+      })
+    ).toEqual({
+      placeholder: `tracedSVG`,
+    })
+
+    expect(
+      normalizeProps({
+        placeholder: `tracedSVG`,
+      })
+    ).toEqual({
+      placeholder: `tracedSVG`,
+    })
+
+    expect(
+      normalizeProps({
+        placeholder: `tracedSvg`,
+      })
+    ).toEqual({
+      placeholder: `tracedSVG`,
+    })
+  })
+})

packages/gatsby-plugin-image/src/babel-helpers.ts

@@ -2,6 +2,7 @@ import { murmurhash } from "babel-plugin-remove-graphql-queries/murmur"
 import { JSXOpeningElement } from "@babel/types"
 import { NodePath } from "@babel/core"
 import { getAttributeValues } from "babel-jsx-utils"
+import camelCase from "camelcase"
 
 export const SHARP_ATTRIBUTES = new Set([
   `src`,
@@ -22,12 +23,37 @@ export const SHARP_ATTRIBUTES = new Set([
   `background`,
 ])
 
+export function normalizeProps(
+  props: Record<string, unknown>
+): Record<string, unknown> {
+  const out = {
+    ...props,
+  }
+
+  if (out.layout) {
+    out.layout = camelCase(out.layout as string)
+  }
+
+  if (out.placeholder) {
+    out.placeholder = camelCase(out.placeholder as string)
+    if (out.placeholder === `tracedSvg`) {
+      out.placeholder = `tracedSVG`
+    }
+  }
+
+  if (Array.isArray(out.formats)) {
+    out.formats = out.formats.map((format: string) => format.toLowerCase())
+  }
+
+  return out
+}
+
 export function evaluateImageAttributes(
   nodePath: NodePath<JSXOpeningElement>,
   onError?: (prop: string) => void
 ): Record<string, unknown> {
   // Only get attributes that we need for generating the images
-  return getAttributeValues(nodePath, onError, SHARP_ATTRIBUTES)
+  return normalizeProps(getAttributeValues(nodePath, onError, SHARP_ATTRIBUTES))
 }
 
 export function hashOptions(options: unknown): string {

packages/gatsby-plugin-image/src/components/static-image.server.tsx

@@ -111,6 +111,8 @@ const checkDimensionProps: PropTypes.Validator<number> = (
   return PropTypes.number(props, propName, ...rest)
 }
 
+const validLayouts = new Set([`fixed`, `fluid`, `constrained`])
+
 export const propTypes = {
   src: PropTypes.string.isRequired,
   alt: PropTypes.string.isRequired,
@@ -119,6 +121,18 @@ export const propTypes = {
   maxHeight: checkDimensionProps,
   maxWidth: checkDimensionProps,
   sizes: PropTypes.string,
+  layout: (props: IStaticImageProps & IPrivateProps): Error | undefined => {
+    if (props.layout === undefined) {
+      return undefined
+    }
+    if (validLayouts.has(props.layout.toLowerCase())) {
+      return undefined
+    }
+
+    return new Error(
+      `Invalid value ${props.layout}" provided for prop "layout". Defaulting to "fixed". Valid values are "fixed", "fluid" or "constrained"`
+    )
+  },
 }
 
 StaticImage.displayName = `StaticImage`