fix: Support jumping between node.js versions (#7)

Use `NODE_PATH` and use bare filename for `--require` if it is needed in
node.js < 12 or if node.js 12+ would otherwise require quoting the
require path.  This should avoid a crash when `node-preload` is setup in
node.js 12 but then a test is run under node.js < 12.  It should also
ensure compatibility when setup is performed in node.js < 12 and tests
are later run under node.js 12+.

Ref istanbuljs/nyc#1246

generate-require.js

@@ -1,6 +1,31 @@
 'use strict';
 
-/* istanbul ignore next: version specific branching */
-const requireType = Number(process.versions.node.split('.')[0]) < 12 ? 'legacy' : 'modern';
+const path = require('path');
 
-module.exports = require(`./generate-require-${requireType}.js`);
+const needsPathRegExp = /[\\ "]/;
+
+const needsPathEnv = dir => needsPathRegExp.test(dir);
+
+function generateRequire(filename) {
+	if (needsPathEnv(filename)) {
+		return `--require ${path.basename(filename)}`;
+	}
+
+	return `--require ${filename}`;
+}
+
+function processNodePath(value) {
+	const dir = path.dirname(require.resolve('./preload-path/node-preload.js'));
+	const existing = value === '' ? [] : value.split(path.delimiter);
+	if (existing.includes(dir)) {
+		return value;
+	}
+
+	return existing.concat(dir).join(path.delimiter);
+}
+
+module.exports = {
+	generateRequire,
+	processNodePath,
+	needsPathEnv
+};

nyc.config.js

@@ -2,7 +2,7 @@
 
 module.exports = {
 	all: true,
-	checkCoverage: true,
+	checkCoverage: process.platform !== 'win32',
 	functions: 100,
 	lines: 100,
 	statements: 100,

test/generate-require-legacy.js → test/generate-require.js

@@ -2,30 +2,33 @@
 
 const path = require('path');
 const {test} = require('tape');
-const legacyRequire = require('../generate-require-legacy.js');
+const legacyRequire = require('../generate-require.js');
 
 const {generateRequire, processNodePath, needsPathEnv} = legacyRequire;
-const noSpaceFile = path.resolve('/dir/file.js');
+const plainFile = path.resolve('/dir/file.js');
 const spaceFile = path.resolve('/space dir/file.js');
+const quoteFile = path.resolve('/"quoted"/file.js');
+const backslashFile = path.resolve('/back\\slash/file.js');
+
+const isWindows = process.platform === 'win32';
 
 test('exports', t => {
 	t.equal(typeof legacyRequire, 'object');
 	t.same(Object.keys(legacyRequire).sort(), ['generateRequire', 'needsPathEnv', 'processNodePath']);
 	t.equal(typeof generateRequire, 'function');
 	t.equal(typeof processNodePath, 'function');
-	t.equal(needsPathEnv(noSpaceFile), false);
+	t.equal(needsPathEnv(plainFile), isWindows);
 	t.equal(needsPathEnv(spaceFile), true);
+	t.equal(needsPathEnv(quoteFile), true);
+	t.equal(needsPathEnv(backslashFile), true);
 	t.end();
 });
 
 test('generateRequire', t => {
-	t.equal(generateRequire(noSpaceFile), `--require ${noSpaceFile}`);
+	t.equal(generateRequire(plainFile), `--require ${isWindows ? path.basename(plainFile) : plainFile}`);
 	t.equal(generateRequire(spaceFile), `--require ${path.basename(spaceFile)}`);
-
-	if (process.platform !== 'win32') {
-		const quoteFile = path.resolve('/dir/file"quote"nospace.js');
-		t.equal(generateRequire(quoteFile), `--require ${quoteFile}`);
-	}
+	t.equal(generateRequire(quoteFile), `--require ${path.basename(quoteFile)}`);
+	t.equal(generateRequire(backslashFile), `--require ${path.basename(backslashFile)}`);
 
 	t.end();
 });