Fix #113 (handle exponents on coefficients of polynomial terms) (#123)

google · Feb 10, 2017 · b222cbf · b222cbf
1 parent b029a41
commit b222cbf
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diff --git a/lib/util/removeUnnecessaryParens.js b/lib/util/removeUnnecessaryParens.js
@@ -50,6 +50,19 @@ function removeUnnecessaryParensSearch(node) {
 // unncessary parens around operators that can't be simplified further.
 // Returns a node.
 function removeUnnecessaryParensInOperatorNode(node) {
+  // Special case: if the node is an exponent node and the base
+  // is an operator, we should keep the parentheses for the base.
+  // e.g. (2x)^2 -> (2x)^2 instead of 2x^2
+  if (node.op === '^' && Node.Type.isParenthesis(node.args[0])) {
+    const base = node.args[0];
+    if (Node.Type.isOperator(base.content)) {
+      base.content = removeUnnecessaryParensSearch(base.content);
+      node.args[1] = removeUnnecessaryParensSearch(node.args[1]);
+
+      return node;
+    }
+  }
+
   node.args.forEach((child, i) => {
     node.args[i] = removeUnnecessaryParensSearch(child);
   });

diff --git a/test/util/removeUnnecessaryParens.test.js b/test/util/removeUnnecessaryParens.test.js
@@ -23,6 +23,8 @@ describe('removeUnnecessaryParens', function () {
     ['((4+5)) + ((2^3))', '(4 + 5) + 2^3'],
     ['(2x^6 + -50 x^2) - (x^4)', '2x^6 - 50x^2 - x^4'],
     ['(x+4) - (12 + x)', 'x + 4 - (12 + x)'],
+    ['(2x)^2', '(2x)^2'],
+    ['((4+x)-5)^(2)', '(4 + x - 5)^2'],
   ];
   tests.forEach(t => testRemoveUnnecessaryParens(t[0], t[1]));
 });