Introduce HyperScript-like DSL for constructing DOM (#281)

packages/alfa-aria/test/get-name.spec.tsx

@@ -35,7 +35,7 @@ test("getName() computes the text alternative of a button with text within a spa
 test("getName() ignores non-visible nodes", (t) => {
   const button = Element.fromElement(
     <button>
-      Button <span style="display: none">Hidden</span>
+      Button <span style={{ display: "none" }}>Hidden</span>
     </button>
   );
 

packages/alfa-dom/h.ts

@@ -0,0 +1 @@
+export * from "./src/h";

packages/alfa-dom/package.json

@@ -20,7 +20,6 @@
     "src/**/*.d.ts"
   ],
   "dependencies": {
-    "@siteimprove/alfa-css": "^0.2.0",
     "@siteimprove/alfa-earl": "^0.2.0",
     "@siteimprove/alfa-equatable": "^0.2.0",
     "@siteimprove/alfa-iterable": "^0.2.0",
@@ -29,8 +28,7 @@
     "@siteimprove/alfa-mapper": "^0.2.0",
     "@siteimprove/alfa-option": "^0.2.0",
     "@siteimprove/alfa-predicate": "^0.2.0",
-    "@siteimprove/alfa-sequence": "^0.2.0",
-    "@siteimprove/alfa-slice": "^0.2.0"
+    "@siteimprove/alfa-sequence": "^0.2.0"
   },
   "devDependencies": {
     "@siteimprove/alfa-test": "^0.2.0"

packages/alfa-dom/src/h.ts

@@ -0,0 +1,291 @@
+import { Namespace } from "./namespace";
+
+import { Node } from "./node";
+import { Attribute } from "./node/attribute";
+import { Document } from "./node/document";
+import { Element } from "./node/element";
+import { Fragment } from "./node/fragment";
+import { Text } from "./node/text";
+import { Type } from "./node/type";
+
+import { Block } from "./style/block";
+import { Declaration } from "./style/declaration";
+import {
+  Rule,
+  FontFaceRule,
+  KeyframeRule,
+  KeyframesRule,
+  MediaRule,
+  NamespaceRule,
+  PageRule,
+  StyleRule,
+  SupportsRule,
+} from "./style/rule";
+import { Sheet } from "./style/sheet";
+
+const { entries } = Object;
+
+export function h(
+  name: string,
+  attributes: Array<Attribute.JSON> | Record<string, string | boolean> = [],
+  children: Array<Node.JSON | string> = [],
+  style: Array<Declaration.JSON> | Record<string, string> = []
+): Element.JSON {
+  return h.element(Namespace.HTML, null, name, attributes, children, style);
+}
+
+export namespace h {
+  export function element(
+    namespace: string | null,
+    prefix: string | null,
+    name: string,
+    attributes: Array<Attribute.JSON> | Record<string, string | boolean> = [],
+    children: Array<Node.JSON | string> = [],
+    style: Array<Declaration.JSON> | Record<string, string> = []
+  ): Element.JSON {
+    attributes = Array.isArray(attributes)
+      ? attributes
+      : entries(attributes).reduce<Array<Attribute.JSON>>(
+          (attributes, [name, value]) => {
+            if (value === false) {
+              return attributes;
+            }
+
+            return [
+              ...attributes,
+              h.attribute(hyphenate(name), value === true ? "" : value),
+            ];
+          },
+          []
+        );
+
+    style = h.block(style);
+
+    if (style.length > 0) {
+      attributes = [
+        ...attributes,
+        h.attribute("style", Block.fromBlock(style).toString()),
+      ];
+    }
+
+    const json: Element.JSON = {
+      type: "element",
+      namespace,
+      prefix,
+      name,
+      attributes,
+      children: children.map((child) =>
+        typeof child === "string" ? h.text(child) : child
+      ),
+      style,
+      shadow: null,
+      content: null,
+    };
+
+    switch (name) {
+      case "svg":
+        renamespace(json, Namespace.SVG);
+        break;
+
+      case "math":
+        renamespace(json, Namespace.MathML);
+    }
+
+    return json;
+  }
+  export function attribute(name: string, value: string): Attribute.JSON {
+    return {
+      type: "attribute",
+      namespace: null,
+      prefix: null,
+      name,
+      value,
+    };
+  }
+
+  export function text(data: string): Text.JSON {
+    return {
+      type: "text",
+      data,
+    };
+  }
+
+  export function document(
+    children: Array<Node.JSON | string>,
+    style: Array<Sheet.JSON> = []
+  ): Document.JSON {
+    return {
+      type: "document",
+      children: children.map((child) =>
+        typeof child === "string" ? text(child) : child
+      ),
+      style,
+    };
+  }
+
+  export function type(
+    name: string,
+    publicId: string | null = null,
+    systemId: string | null = null
+  ): Type.JSON {
+    return {
+      type: "type",
+      name,
+      publicId,
+      systemId,
+    };
+  }
+
+  export function fragment(children: Array<Node.JSON | string>): Fragment.JSON {
+    return {
+      type: "fragment",
+      children: children.map((child) =>
+        typeof child === "string" ? text(child) : child
+      ),
+    };
+  }
+
+  export function sheet(
+    rules: Array<Rule.JSON>,
+    disabled: boolean = false,
+    condition: string | null = null
+  ): Sheet.JSON {
+    return {
+      rules,
+      disabled,
+      condition,
+    };
+  }
+
+  export function block(
+    declarations: Array<Declaration.JSON> | Record<string, string>
+  ): Block.JSON {
+    return Array.isArray(declarations)
+      ? declarations
+      : entries(declarations).map(([name, value]) => {
+          const important = value.endsWith("!important");
+
+          value = value.replace(/\s+?!important$/, "");
+
+          return {
+            name: hyphenate(name),
+            value,
+            important,
+          };
+        });
+  }
+
+  export function declaration(
+    name: string,
+    value: string,
+    important: boolean = false
+  ): Declaration.JSON {
+    return {
+      name,
+      value,
+      important,
+    };
+  }
+
+  export namespace rule {
+    export function fontFace(
+      declarations: Array<Declaration.JSON> | Record<string, string>
+    ): FontFaceRule.JSON {
+      return {
+        type: "font-face",
+        style: block(declarations),
+      };
+    }
+
+    export function keyframe(
+      key: string,
+      declarations: Array<Declaration.JSON> | Record<string, string>
+    ): KeyframeRule.JSON {
+      return {
+        type: "keyframe",
+        key,
+        style: block(declarations),
+      };
+    }
+
+    export function keyframes(
+      name: string,
+      rules: Array<Rule.JSON>
+    ): KeyframesRule.JSON {
+      return {
+        type: "keyframes",
+        name,
+        rules,
+      };
+    }
+
+    export function media(
+      condition: string,
+      rules: Array<Rule.JSON>
+    ): MediaRule.JSON {
+      return {
+        type: "media",
+        condition,
+        rules,
+      };
+    }
+
+    export function namespace(
+      namespace: string,
+      prefix: string | null = null
+    ): NamespaceRule.JSON {
+      return {
+        type: "namespace",
+        namespace,
+        prefix,
+      };
+    }
+
+    export function page(
+      selector: string,
+      declarations: Array<Declaration.JSON> | Record<string, string>
+    ): PageRule.JSON {
+      return {
+        type: "page",
+        selector,
+        style: block(declarations),
+      };
+    }
+
+    export function style(
+      selector: string,
+      declarations: Array<Declaration.JSON> | Record<string, string>
+    ): StyleRule.JSON {
+      return {
+        type: "style",
+        selector,
+        style: block(declarations),
+      };
+    }
+
+    export function supports(
+      condition: string,
+      rules: Array<Rule.JSON>
+    ): SupportsRule.JSON {
+      return {
+        type: "supports",
+        condition,
+        rules,
+      };
+    }
+  }
+}
+
+function hyphenate(value: string): string {
+  return value.replace(/[A-Z]/g, (letter) => `-${letter.toLowerCase()}`);
+}
+
+function renamespace(element: Element.JSON, namespace: Namespace): void {
+  element.namespace = namespace;
+
+  for (const child of element.children) {
+    if (child.type === "element") {
+      renamespace(child as Element.JSON, namespace);
+    }
+  }
+}

packages/alfa-dom/src/index.ts

@@ -1,3 +1,5 @@
+export * from "./h";
+export * from "./jsx";
 export * from "./namespace";
 export * from "./node";
 export * from "./node/attribute";