build: only build wasm on linux

.travis.yml

@@ -18,9 +18,9 @@ os:
   - osx
   - linux
 before_install:
-  - docker run -dit --name emscripten -v $(pwd):/src trzeci/emscripten:sdk-incoming-64bit bash
+  - '[[ $TRAVIS_OS_NAME == linux ]] && docker run -dit --name emscripten -v $(pwd):/src trzeci/emscripten-slim:sdk-incoming-64bit bash'
 before_script:
-  - npm run build:wasm
+  - '[[ $TRAVIS_OS_NAME == linux ]] && docker exec -it emscripten npm run build:wasm'
 before_deploy:
   - ARCHIVE_NAME="${TRAVIS_TAG:-latest}-$TRAVIS_OS_NAME-`uname -m`.tar"
   - npm run prebuild

package.json

@@ -50,6 +50,7 @@
     "eslint-plugin-json": "^2.1.0",
     "eslint-plugin-package-json": "^0.1.4",
     "eslint-plugin-prettier": "^3.1.2",
+    "is-ci": "^2.0.0",
     "jest": "^25.1.0",
     "jscheck": "^0.2.0",
     "node-addon-api": "^2.0.0",

test/test.random.js

@@ -1,7 +1,14 @@
+const isCI = require('is-ci');
 const JSC = require('jscheck');
 const natural = require('../damerau-levenshtein.natural');
 const native = require('../damerau-levenshtein.native');
-const wasm = require('../damerau-levenshtein.wasm');
+/** @type {typeof import('../damerau-levenshtein.wasm')} */
+let wasm;
+try {
+  wasm = require('../damerau-levenshtein.wasm');
+} catch (err) {
+  console.warn('Failed to load wasm:', err);
+}
 
 const opts = [];
 for (const insertion_cost of [0.5, 1]) {
@@ -59,12 +66,14 @@ afterAll(() => {
     '\n  Overall:',
     (totalNaturalTime / totalNapiTime).toFixed(1)
   );
-  console.log(
-    'Wasm speedup:\n  Mean:',
-    (totalWasmFactors / wasmSpeedupFactors.length).toFixed(1),
-    '\n  Overall:',
-    (totalNaturalTime / totalWasmTime).toFixed(1)
-  );
+  if (wasm) {
+    console.log(
+      'Wasm speedup:\n  Mean:',
+      (totalWasmFactors / wasmSpeedupFactors.length).toFixed(1),
+      '\n  Overall:',
+      (totalNaturalTime / totalWasmTime).toFixed(1)
+    );
+  }
 
   if (mismatches.length > 0) {
     console.error('Failing options:', mismatches);
@@ -140,6 +149,18 @@ for (const options of opts) {
       expect(factor).toBeGreaterThan(2);
     });
 
+    if (!wasm) {
+      if (isCI && process.platform === 'darwin') {
+        it.todo('should generate correct distances with wasm code');
+      } else {
+        it('should generate correct distances with wasm code', (done) => {
+          done.fail('wasm did not load');
+        });
+      }
+      it.todo('should be faster than natural in wasm mode');
+      return;
+    }
+
     let wasmTime;
     it(
       'should generate correct distances with wasm code',