js-on-sx: var hoisting — hoist var names as undefined before funcdecls

lib/js/test.sh

@@ -1333,6 +1333,15 @@ cat > "$TMPFILE" << 'EPOCHS'
 (epoch 4203)
 (eval "(let ((toks (js-tokenize \"a b\"))) (get (nth toks 1) :nl))")
 
+(epoch 4300)
+(eval "(js-eval \"var x = 5; x\")")
+(epoch 4301)
+(eval "(js-eval \"function f() { return x; var x = 42; } f()\")")
+(epoch 4302)
+(eval "(js-eval \"function f() { var y = 7; return y; } f()\")")
+(epoch 4303)
+(eval "(js-eval \"function f() { var z; z = 3; return z; } f()\")")
+
 EPOCHS
 
 
@@ -2058,6 +2067,11 @@ check 4201 "return+space+val → val"        '42'
 check 4202 "nl-before flag set after newline" 'true'
 check 4203 "nl-before flag false on same line" 'false'
 
+check 4300 "var decl program-level"         '5'
+check 4301 "var hoisted before use → undef" '"js-undefined"'
+check 4302 "var in function body"           '7'
+check 4303 "var then set in function"       '3'
+
 TOTAL=$((PASS + FAIL))
 if [ $FAIL -eq 0 ]; then
   echo "✓ $PASS/$TOTAL JS-on-SX tests passed"