Commit node_modules

paige/node_modules/katex/src/ParseError.js

@@ -0,0 +1,76 @@
+// @flow
+import {Token} from "./Token";
+
+import type {AnyParseNode} from "./parseNode";
+
+/**
+ * This is the ParseError class, which is the main error thrown by KaTeX
+ * functions when something has gone wrong. This is used to distinguish internal
+ * errors from errors in the expression that the user provided.
+ *
+ * If possible, a caller should provide a Token or ParseNode with information
+ * about where in the source string the problem occurred.
+ */
+class ParseError {
+    position: number | void;
+        // Error position based on passed-in Token or ParseNode.
+
+    constructor(
+        message: string,               // The error message
+        token?: ?Token | AnyParseNode, // An object providing position information
+    ): Error {
+        let error = "KaTeX parse error: " + message;
+        let start;
+
+        const loc = token && token.loc;
+        if (loc && loc.start <= loc.end) {
+            // If we have the input and a position, make the error a bit fancier
+
+            // Get the input
+            const input = loc.lexer.input;
+
+            // Prepend some information
+            start = loc.start;
+            const end = loc.end;
+            if (start === input.length) {
+                error += " at end of input: ";
+            } else {
+                error += " at position " + (start + 1) + ": ";
+            }
+
+            // Underline token in question using combining underscores
+            const underlined = input.slice(start, end).replace(/[^]/g, "$&\u0332");
+
+            // Extract some context from the input and add it to the error
+            let left;
+            if (start > 15) {
+                left = "…" + input.slice(start - 15, start);
+            } else {
+                left = input.slice(0, start);
+            }
+            let right;
+            if (end + 15 < input.length) {
+                right = input.slice(end, end + 15) + "…";
+            } else {
+                right = input.slice(end);
+            }
+            error += left + underlined + right;
+
+        }
+
+        // Some hackery to make ParseError a prototype of Error
+        // See http://stackoverflow.com/a/8460753
+        const self = new Error(error);
+        self.name = "ParseError";
+        // $FlowFixMe
+        self.__proto__ = ParseError.prototype;
+        // $FlowFixMe
+        self.position = start;
+        return self;
+    }
+}
+
+// $FlowFixMe More hackery
+ParseError.prototype.__proto__ = Error.prototype;
+
+export default ParseError;