From 97101929ce6b1b79f2b7185199d41405ac305cfb Mon Sep 17 00:00:00 2001
From: Kirk Swenson <kswenson@users.noreply.github.com>
Date: Thu, 25 Jul 2024 19:24:54 -0700
Subject: [PATCH] fix: parsing of inequality operators in formulas (#1377)

---
 .../formula/utils/canonicalization-utils.test.ts  | 15 ++++++++++++++-
 .../formula/utils/canonicalization-utils.ts       |  4 +++-
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/v3/src/models/formula/utils/canonicalization-utils.test.ts b/v3/src/models/formula/utils/canonicalization-utils.test.ts
index ea9b6bd789..03aebb8ca7 100644
--- a/v3/src/models/formula/utils/canonicalization-utils.test.ts
+++ b/v3/src/models/formula/utils/canonicalization-utils.test.ts
@@ -77,10 +77,23 @@ describe("customizeDisplayFormula", () => {
     expect(customizeDisplayFormula("a = b")).toEqual("a == b")
     expect(customizeDisplayFormula("a = b = c")).toEqual("a == b == c")
   })
-  it("doesn't replace unequality operator", () => {
+  it("doesn't replace double equality operator", () => {
+    expect(customizeDisplayFormula("a == 1")).toEqual("a == 1")
+    expect(customizeDisplayFormula("a == b")).toEqual("a == b")
+    expect(customizeDisplayFormula("a == b = c = d == e")).toEqual("a == b == c == d == e")
+  })
+  it("doesn't replace inequality operators", () => {
     expect(customizeDisplayFormula("a != 1")).toEqual("a != 1")
     expect(customizeDisplayFormula("a != b")).toEqual("a != b")
     expect(customizeDisplayFormula("a != b = c = d != e")).toEqual("a != b == c == d != e")
+
+    expect(customizeDisplayFormula("a <= 1")).toEqual("a <= 1")
+    expect(customizeDisplayFormula("a <= b")).toEqual("a <= b")
+    expect(customizeDisplayFormula("a <= b = c = d <= e")).toEqual("a <= b == c == d <= e")
+
+    expect(customizeDisplayFormula("a >= 1")).toEqual("a >= 1")
+    expect(customizeDisplayFormula("a >= b")).toEqual("a >= b")
+    expect(customizeDisplayFormula("a >= b = c = d >= e")).toEqual("a >= b == c == d >= e")
   })
 })
 
diff --git a/v3/src/models/formula/utils/canonicalization-utils.ts b/v3/src/models/formula/utils/canonicalization-utils.ts
index e3d2fe0a35..3c00bf73b3 100644
--- a/v3/src/models/formula/utils/canonicalization-utils.ts
+++ b/v3/src/models/formula/utils/canonicalization-utils.ts
@@ -31,7 +31,9 @@ export const makeDisplayNamesSafe = (formula: string) => {
 export const customizeDisplayFormula = (formula: string) => {
   // Over time, this function might grow significantly and require more advanced parsing of the formula.
   // Replace all the assignment operators with equality operators, as CODAP v2 uses a single "=" for equality check.
-  return formula.replace(/(?<!!)=(?!=)/g, "==")
+  // Regular expression developed with the help of ChatGPT.
+  // Matches `=` when not preceded by '<', '>', '!', or '=` and not followed by `=`, preserving white space.
+  return formula.replace(/(?<!<|>|!|=)(\s*)=(\s*)(?!=)/g, "$1==$2")
 }
 
 export const preprocessDisplayFormula = (formula: string) => customizeDisplayFormula(makeDisplayNamesSafe(formula))