planning

node_modules/graphql/language/source.js.flow

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+// @flow strict
+import { SYMBOL_TO_STRING_TAG } from '../polyfills/symbols';
+
+import inspect from '../jsutils/inspect';
+import devAssert from '../jsutils/devAssert';
+import instanceOf from '../jsutils/instanceOf';
+
+type Location = {|
+  line: number,
+  column: number,
+|};
+
+/**
+ * A representation of source input to GraphQL. The `name` and `locationOffset` parameters are
+ * optional, but they are useful for clients who store GraphQL documents in source files.
+ * For example, if the GraphQL input starts at line 40 in a file named `Foo.graphql`, it might
+ * be useful for `name` to be `"Foo.graphql"` and location to be `{ line: 40, column: 1 }`.
+ * The `line` and `column` properties in `locationOffset` are 1-indexed.
+ */
+export class Source {
+  body: string;
+  name: string;
+  locationOffset: Location;
+
+  constructor(
+    body: string,
+    name: string = 'GraphQL request',
+    locationOffset: Location = { line: 1, column: 1 },
+  ) {
+    devAssert(
+      typeof body === 'string',
+      `Body must be a string. Received: ${inspect(body)}.`,
+    );
+
+    this.body = body;
+    this.name = name;
+    this.locationOffset = locationOffset;
+    devAssert(
+      this.locationOffset.line > 0,
+      'line in locationOffset is 1-indexed and must be positive.',
+    );
+    devAssert(
+      this.locationOffset.column > 0,
+      'column in locationOffset is 1-indexed and must be positive.',
+    );
+  }
+
+  // $FlowFixMe[unsupported-syntax] Flow doesn't support computed properties yet
+  get [SYMBOL_TO_STRING_TAG]() {
+    return 'Source';
+  }
+}
+
+/**
+ * Test if the given value is a Source object.
+ *
+ * @internal
+ */
+declare function isSource(source: mixed): boolean %checks(source instanceof
+  Source);
+// eslint-disable-next-line no-redeclare
+export function isSource(source) {
+  return instanceOf(source, Source);
+}