Fix compat logic

Fixes #77

scripts/build-prefixes.js

@@ -222,13 +222,14 @@ let prefixMapping = {
 
 let enumify = (f) => f.replace(/^@([a-z])/, (_, x) => 'At' + x.toUpperCase()).replace(/^::([a-z])/, (_, x) => 'PseudoElement' + x.toUpperCase()).replace(/^:([a-z])/, (_, x) => 'PseudoClass' + x.toUpperCase()).replace(/(^|-)([a-z])/g, (_, a, x) => x.toUpperCase())
 
+let allBrowsers = Object.keys(browsers).filter(b => !(b in BROWSER_MAPPING)).sort();
 let targets = `// This file is autogenerated by build-prefixes.js. DO NOT EDIT!
 
 use serde::{Deserialize, Serialize};
 
 #[derive(Serialize, Debug, Deserialize, Clone, Copy, Default)]
 pub struct Browsers {
-  pub ${Object.keys(browsers).filter(b => !(b in BROWSER_MAPPING)).sort().join(': Option<u32>,\n  pub ')}: Option<u32>
+  pub ${allBrowsers.join(': Option<u32>,\n  pub ')}: Option<u32>
 }
 `;
 
@@ -237,7 +238,7 @@ fs.writeFileSync('src/targets.rs', targets);
 let targets_dts = `// This file is autogenerated by build-prefixes.js. DO NOT EDIT!
 
 export interface Targets {
-  ${Object.keys(browsers).filter(b => !(b in BROWSER_MAPPING)).sort().join('?: number,\n  ')}?: number
+  ${allBrowsers.join('?: number,\n  ')}?: number
 }
 `;
 
@@ -315,19 +316,20 @@ pub enum Feature {
 impl Feature {
   pub fn is_compatible(&self, browsers: Browsers) -> bool {
     match self {
-      ${[...compat].map(([features, browsers]) =>
-        `${features.map(name => `Feature::${enumify(name)}`).join(' |\n      ')} => {` + (Object.entries(browsers).length === 0 ? '}' : `
-        ${Object.entries(browsers).map(([browser, min]) =>
+      ${[...compat].map(([features, supportedBrowsers]) =>
+        `${features.map(name => `Feature::${enumify(name)}`).join(' |\n      ')} => {` + (Object.entries(supportedBrowsers).length === 0 ? '\n        return false\n      }' : `
+        ${Object.entries(supportedBrowsers).map(([browser, min]) =>
             `if let Some(version) = browsers.${browser} {
-          if version >= ${min} {
-            return true
+          if version < ${min} {
+            return false
           }
-        }`
-          ).join('\n        ')}
+        }`).join('\n        ')}${Object.keys(supportedBrowsers).length === allBrowsers.length ? '' : `\n        if ${allBrowsers.filter(b => !supportedBrowsers[b]).map(browser => `browsers.${browser}.is_some()`).join(' || ')} {
+          return false
+        }`}
       }`
       )).join('\n      ')}
     }
-    false
+    true
   }
 }
 `;