1 files changed, 188 insertions, 0 deletions
diff --git a/src/gql.ts b/src/gql.ts
new file mode 100644
index 0000000..6ccf9cd
--- /dev/null
+++ b/src/gql.ts
@@ -0,0 +1,188 @@
+
+
+
+/// import
+
+import { parse } from "npm:graphql@16.6.0";
+import type { DefinitionNode, DocumentNode, Location } from "npm:graphql@16.6.0";
+
+/// util
+
+const docCache = new Map<string, DocumentNode>();         // a map docString -> graphql document
+const fragmentSourceMap = new Map<string, Set<string>>(); // a map fragmentName -> [normalized source]
+
+let allowLegacyFragmentVariables = false;
+let printFragmentWarnings = true;
+
+
+
+/// export
+
+export function disableExperimentalFragmentVariables() {
+  allowLegacyFragmentVariables = false;
+}
+
+export function disableFragmentWarnings() {
+  printFragmentWarnings = false;
+}
+
+export function enableExperimentalFragmentVariables() {
+  allowLegacyFragmentVariables = true;
+}
+
+export function gql(literals: string | readonly string[], ...args: any[]) {
+  /**
+   * Create a GraphQL AST from template literal
+   * @param literals
+   * @param args
+   *
+   * @example
+   * ```ts
+   * import { buildASTSchema, graphql } from "https://deno.land/x/graphql_deno@v15.0.0/mod.ts"
+   * import { gql } from "https://deno.land/x/graphql_tag/mod.ts"
+   *
+   * const typeDefs = gql`
+   *  type Query {
+   *    hello: String
+   *  }
+   * `
+   *
+   * const query = `{ hello }`
+   *
+   * const resolvers = { hello: () => "world" }
+   *
+   * console.log(await graphql(buildASTSchema(typeDefs), query, resolvers))
+   * ```
+   */
+
+  if (typeof literals === "string")
+    literals = [literals];
+
+  let result = literals[0];
+
+  args.forEach((arg, i) => {
+    if (arg && arg.kind === "Document")
+      result += arg.loc.source.body;
+    else
+      result += arg;
+
+    result += literals[i + 1];
+  });
+
+  return parseDocument(result);
+}
+
+export function resetCaches() {
+  docCache.clear();
+  fragmentSourceMap.clear();
+}
+
+
+
+/// helper
+
+function normalize(string: string) {
+  // Strip insignificant whitespace
+  // Note that this could do a lot more, such as reorder fields etc.
+  return string.replace(/[\s,]+/g, " ").trim();
+}
+
+function cacheKeyFromLoc(loc: Location) {
+  return normalize(loc.source.body.substring(loc.start, loc.end));
+}
+
+function processFragments(ast: DocumentNode) {
+  // Take a unstripped parsed document (query/mutation or even fragment), and
+  // check all fragment definitions, checking for name->source uniqueness.
+  // We also want to make sure only unique fragments exist in the document.
+
+  const definitions: DefinitionNode[] = [];
+  const seenKeys = new Set<string>();
+
+  ast.definitions.forEach((fragmentDefinition) => {
+    if (fragmentDefinition.kind === "FragmentDefinition") {
+      const fragmentName = fragmentDefinition.name.value;
+      const sourceKey = cacheKeyFromLoc(fragmentDefinition.loc!);
+
+      // We know something about this fragment
+      let sourceKeySet = fragmentSourceMap.get(fragmentName)!;
+
+      if (sourceKeySet && !sourceKeySet.has(sourceKey)) {
+        // this is a problem because the app developer is trying to register another fragment with
+        // the same name as one previously registered. So, we tell them about it.
+        if (printFragmentWarnings) {
+          console.warn(
+            `Warning: fragment with name ${fragmentName} already exists.\n` +
+            "gql enforces all fragment names across your application to be unique; read more about\n" +
+            "this in the docs: http://dev.apollodata.com/core/fragments.html#unique-names"
+          );
+        }
+      } else if (!sourceKeySet) {
+        fragmentSourceMap.set(fragmentName, (sourceKeySet = new Set()));
+      }
+
+      sourceKeySet.add(sourceKey);
+
+      if (!seenKeys.has(sourceKey)) {
+        seenKeys.add(sourceKey);
+        definitions.push(fragmentDefinition);
+      }
+    } else {
+      definitions.push(fragmentDefinition);
+    }
+  })
+
+  return {
+    ...ast,
+    definitions
+  };
+}
+
+function stripLoc(doc: DocumentNode) {
+  const workSet = new Set<Record<string, any>>(doc.definitions);
+
+  workSet.forEach((node) => {
+    if (node.loc)
+      delete node.loc;
+
+    Object.keys(node).forEach((key) => {
+      const value = node[key];
+
+      if (value && typeof value === "object")
+        workSet.add(value);
+    });
+  });
+
+  const loc = doc.loc as { endToken: unknown; startToken: unknown; };
+
+  if (loc) {
+    delete loc.startToken;
+    delete loc.endToken;
+  }
+
+  return doc;
+}
+
+function parseDocument(source: string) {
+  const cacheKey = normalize(source);
+
+  if (!docCache.has(cacheKey)) {
+    const parsed = parse(source, { allowLegacyFragmentVariables });
+
+    if (!parsed || parsed.kind !== "Document")
+      throw new Error("Not a valid GraphQL document.");
+
+    docCache.set(
+      cacheKey,
+      // check that all "new" fragments inside the documents are consistent with
+      // existing fragments of the same name
+      stripLoc(processFragments(parsed))
+    );
+  }
+
+  return docCache.get(cacheKey)!;
+}
+
+
+
+/// via https://github.com/deno-libs/graphql_tag