From 4904644464bbe5e4fea88e9de3435422b7504f43 Mon Sep 17 00:00:00 2001
From: Zef Hemel <zef@zef.me>
Date: Wed, 4 Oct 2023 09:43:15 +0200
Subject: [PATCH] = semantics

---
 plug-api/lib/query.ts   | 10 ++++++----
 website/Live Queries.md | 21 ++++++++++++---------
 2 files changed, 18 insertions(+), 13 deletions(-)

diff --git a/plug-api/lib/query.ts b/plug-api/lib/query.ts
index 81d68ad..e37af6f 100644
--- a/plug-api/lib/query.ts
+++ b/plug-api/lib/query.ts
@@ -82,8 +82,9 @@ export function evalQueryExpression(
         // Record property is an array, and value is a scalar: find the value in the array
         return val1.includes(val2);
       } else if (Array.isArray(val1) && Array.isArray(val2)) {
-        // Record property is an array, and value is an array: find the value in the array
-        return val1.some((v) => val2.includes(v));
+        // Record property is an array, and value is an array: compare the arrays
+        return val1.length === val2.length &&
+          val1.every((v) => val2.includes(v));
       }
       return val1 == val2;
     }
@@ -92,8 +93,9 @@ export function evalQueryExpression(
         // Record property is an array, and value is a scalar: find the value in the array
         return !val1.includes(val2);
       } else if (Array.isArray(val1) && Array.isArray(val2)) {
-        // Record property is an array, and value is an array: find the value in the array
-        return !val1.some((v) => val2.includes(v));
+        // Record property is an array, and value is an array: compare the arrays
+        return !(val1.length === val2.length &&
+          val1.every((v) => val2.includes(v)));
       }
       return val1 !== val2;
     }
diff --git a/website/Live Queries.md b/website/Live Queries.md
index e38cbb7..86552d4 100644
--- a/website/Live Queries.md	
+++ b/website/Live Queries.md	
@@ -83,15 +83,18 @@ Logical expressions:
 * or: `name = "this" or age > 10`
 
 Binary expressions:
-- `=` equals, e.g. `name = "Pete"`
-- `!=` not equals, e.g. `name != "Pete"`
-- `<` less than, e.g. `age < 10`
-- `<=` less than or equals, e.g. `age <= 10`
-- `>` greater than, e.g. `age > 10`
-- `>=` greater than or equals, e.g. `age >= 10`
-- `=~` to match against a regular expression, e.g. `name =~ /^template\//`
-- `!=~` to not match a regular expression, e.g. `name !=~ /^template\//`
-- `in` member of a list (e.g. `prop in ["foo", "bar"]`)
+* `=` equals.
+  * For scalar values this performance an equivalence tests (e.g. `10 = 10`)
+  * If the left operand is an array and the right operand is _not_, this will will check if the right operand is _included_ in the left operand’s value, e.g. `[1, 2, 3] = 2` will be true.
+  * If both operands are arrays, they will be compared for equivalence ignoring order, so this will be true: `[1, 2, 3] = [3, 2, 1]`
+* `!=` the exact inverse of the meaning of `=`, e.g. `name != "Pete"`
+* `<` less than, e.g. `age < 10`
+* `<=` less than or equals, e.g. `age <= 10`
+* `>` greater than, e.g. `age > 10`
+* `>=` greater than or equals, e.g. `age >= 10`
+* `=~` to match against a regular expression, e.g. `name =~ /^template\//`
+* `!=~` to not match a regular expression, e.g. `name !=~ /^template\//`
+* `in` member of a list (e.g. `prop in ["foo", "bar"]`)
 * `+` addition (can also concatenate strings), e.g. `10 + 12` or `name + "!!!"`
 * `-` subtraction, e.g. `10 - 12`
 * `/` addition, e.g. `10 / 12`