fix: ensure eq always returns a boolean

Author: josdejong

src/compile.test.ts

@@ -37,7 +37,7 @@ for (const [category, testGroups] of Object.entries(testsByCategory)) {
     for (const group of testGroups) {
       describe(group.description, () => {
         for (const currentTest of group.tests) {
-          const description = `input = '${currentTest.input}'`
+          const description = `input=${JSON.stringify(currentTest.input)}, query=${JSON.stringify(currentTest.query)}`
 
           if (isTestException(currentTest)) {
             test(description, () => {

src/is.ts

@@ -1,7 +1,7 @@
 export const isArray = <T>(value: unknown): value is T[] => Array.isArray(value)
 
 export const isObject = (value: unknown): value is object =>
-  value && typeof value === 'object' && !isArray(value)
+  value !== null && typeof value === 'object' && !isArray(value)
 
 export const isString = (value: unknown): value is string => typeof value === 'string'
 
@@ -11,7 +11,7 @@ export const isEqual = <T>(a: T, b: T): boolean => {
     return true
   }
 
-  const bothObject = a && b && typeof a === 'object' && typeof b === 'object'
+  const bothObject = a !== null && b !== null && typeof a === 'object' && typeof b === 'object'
 
   return (
     bothObject &&

test-suite/compile.test.json

@@ -1195,29 +1195,34 @@
           "input": { "a": 3, "b": 2 },
           "query": ["eq", ["get", "a"], ["get", "b"]],
           "output": false
-        }
-      ]
-    },
-    {
-      "category": "eq",
-      "description": "should calculate equal comparing array and number (no type coercion)",
-      "tests": [
-        {
-          "input": null,
-          "query": ["eq", ["array", 2], 2],
-          "output": false
-        }
+        },
+        { "input": { "a": 0.1 }, "query": ["eq", ["get", "a"], 0.1], "output": true },
+        { "input": { "a": 0.1 }, "query": ["eq", ["get", "a"], 0.2], "output": false },
+        { "input": { "a": 0.1 }, "query": ["eq", ["get", "a"], -0.1], "output": false },
+        { "input": null, "query": ["eq", "a", "a"], "output": true },
+        { "input": null, "query": ["eq", "a", "b"], "output": false },
+        { "input": null, "query": ["eq", "a", "A"], "output": false },
+        { "input": null, "query": ["eq", "abc", "abc"], "output": true },
+        { "input": null, "query": ["eq", "abc", "ab"], "output": false },
+        { "input": null, "query": ["eq", true, true], "output": true },
+        { "input": null, "query": ["eq", true, false], "output": false },
+        { "input": null, "query": ["eq", false, true], "output": false },
+        { "input": null, "query": ["eq", false, true], "output": false },
+        { "input": null, "query": ["eq", null, null], "output": true }
       ]
     },
     {
       "category": "eq",
-      "description": "should calculate equal comparing number and string (no type coercion)",
+      "description": "should calculate equal comparing mixed types (no type coercion)",
       "tests": [
-        {
-          "input": null,
-          "query": ["eq", "2", 2],
-          "output": false
-        }
+        { "input": null, "query": ["eq", "2", 2], "output": false },
+        { "input": null, "query": ["eq", "", 0], "output": false },
+        { "input": null, "query": ["eq", 0, ""], "output": false },
+        { "input": null, "query": ["eq", "", null], "output": false },
+        { "input": null, "query": ["eq", null, ""], "output": false },
+        { "input": null, "query": ["eq", 0, null], "output": false },
+        { "input": null, "query": ["eq", ["array"], null], "output": false },
+        { "input": null, "query": ["eq", ["array", 2], 2], "output": false }
       ]
     },
     {
@@ -1550,24 +1555,13 @@
     },
     {
       "category": "ne",
-      "description": "should calculate not equal comparing array and number (no type coercion)",
-      "tests": [
-        {
-          "input": null,
-          "query": ["ne", ["array", 2], 2],
-          "output": true
-        }
-      ]
-    },
-    {
-      "category": "ne",
-      "description": "should calculate not equal comparing number and string (no type coercion)",
+      "description": "should calculate not equal comparing mixed types (no type coercion)",
       "tests": [
-        {
-          "input": null,
-          "query": ["ne", "2", 2],
-          "output": true
-        }
+        { "input": null, "query": ["ne", "2", 2], "output": true },
+        { "input": null, "query": ["ne", "", 0], "output": true },
+        { "input": null, "query": ["ne", "", null], "output": true },
+        { "input": null, "query": ["ne", 0, null], "output": true },
+        { "input": null, "query": ["ne", ["array", 2], 2], "output": true }
       ]
     },
     {