Commit node_modules

paige/node_modules/katex/src/SourceLocation.js

@@ -0,0 +1,42 @@
+// @flow
+import type {LexerInterface} from "./Token";
+
+/**
+ * Lexing or parsing positional information for error reporting.
+ * This object is immutable.
+ */
+export default class SourceLocation {
+    // The + prefix indicates that these fields aren't writeable
+    +lexer: LexerInterface; // Lexer holding the input string.
+    +start: number;         // Start offset, zero-based inclusive.
+    +end: number;           // End offset, zero-based exclusive.
+
+    constructor(lexer: LexerInterface, start: number, end: number) {
+        this.lexer = lexer;
+        this.start = start;
+        this.end = end;
+    }
+
+    /**
+     * Merges two `SourceLocation`s from location providers, given they are
+     * provided in order of appearance.
+     * - Returns the first one's location if only the first is provided.
+     * - Returns a merged range of the first and the last if both are provided
+     *   and their lexers match.
+     * - Otherwise, returns null.
+     */
+    static range(
+        first?: {loc: ?SourceLocation},
+        second?: {loc: ?SourceLocation},
+    ): ?SourceLocation {
+        if (!second) {
+            return first && first.loc;
+        } else if (!first || !first.loc || !second.loc ||
+                   first.loc.lexer !== second.loc.lexer) {
+            return null;
+        } else {
+            return new SourceLocation(
+                    first.loc.lexer, first.loc.start, second.loc.end);
+        }
+    }
+}