planning

node_modules/graphql/language/printLocation.js.flow

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+// @flow strict
+import type { Source } from './source';
+import type { Location } from './ast';
+import type { SourceLocation } from './location';
+import { getLocation } from './location';
+
+/**
+ * Render a helpful description of the location in the GraphQL Source document.
+ */
+export function printLocation(location: Location): string {
+  return printSourceLocation(
+    location.source,
+    getLocation(location.source, location.start),
+  );
+}
+
+/**
+ * Render a helpful description of the location in the GraphQL Source document.
+ */
+export function printSourceLocation(
+  source: Source,
+  sourceLocation: SourceLocation,
+): string {
+  const firstLineColumnOffset = source.locationOffset.column - 1;
+  const body = whitespace(firstLineColumnOffset) + source.body;
+
+  const lineIndex = sourceLocation.line - 1;
+  const lineOffset = source.locationOffset.line - 1;
+  const lineNum = sourceLocation.line + lineOffset;
+
+  const columnOffset = sourceLocation.line === 1 ? firstLineColumnOffset : 0;
+  const columnNum = sourceLocation.column + columnOffset;
+  const locationStr = `${source.name}:${lineNum}:${columnNum}\n`;
+
+  const lines = body.split(/\r\n|[\n\r]/g);
+  const locationLine = lines[lineIndex];
+
+  // Special case for minified documents
+  if (locationLine.length > 120) {
+    const subLineIndex = Math.floor(columnNum / 80);
+    const subLineColumnNum = columnNum % 80;
+    const subLines = [];
+    for (let i = 0; i < locationLine.length; i += 80) {
+      subLines.push(locationLine.slice(i, i + 80));
+    }
+
+    return (
+      locationStr +
+      printPrefixedLines([
+        [`${lineNum}`, subLines[0]],
+        ...subLines.slice(1, subLineIndex + 1).map((subLine) => ['', subLine]),
+        [' ', whitespace(subLineColumnNum - 1) + '^'],
+        ['', subLines[subLineIndex + 1]],
+      ])
+    );
+  }
+
+  return (
+    locationStr +
+    printPrefixedLines([
+      // Lines specified like this: ["prefix", "string"],
+      [`${lineNum - 1}`, lines[lineIndex - 1]],
+      [`${lineNum}`, locationLine],
+      ['', whitespace(columnNum - 1) + '^'],
+      [`${lineNum + 1}`, lines[lineIndex + 1]],
+    ])
+  );
+}
+
+function printPrefixedLines(lines: $ReadOnlyArray<[string, string]>): string {
+  const existingLines = lines.filter(([_, line]) => line !== undefined);
+
+  const padLen = Math.max(...existingLines.map(([prefix]) => prefix.length));
+  return existingLines
+    .map(
+      ([prefix, line]) =>
+        leftPad(padLen, prefix) + (line ? ' | ' + line : ' |'),
+    )
+    .join('\n');
+}
+
+function whitespace(len: number): string {
+  return Array(len + 1).join(' ');
+}
+
+function leftPad(len: number, str: string): string {
+  return whitespace(len - str.length) + str;
+}