src/to-javascript.js

   1 'use strict';
   2
   3 const Promise = require('bluebird');
   4
   5 const fs = Promise.promisifyAll(require('fs'));
   6
   7 const path = require('path');
   8
   9 const jsStringEscape = require('js-string-escape');
  10
  11 const difference = require('lodash.difference');
  12
  13 const debug_ = require('debug');
  14
  15 const debug = debug_('purs-loader');
  16
  17 const debugVerbose = debug_('purs-loader:verbose');
  18
  19 const PsModuleMap = require('./purs-module-map');
  20
  21 function updatePsModuleMap(psModule) {
  22   const options = psModule.options;
  23
  24   const cache = psModule.cache;
  25
  26   const filePurs = psModule.srcPath;
  27
  28   if (!cache.psModuleMap) {
  29     debug('module mapping does not exist');
  30
  31     return PsModuleMap.makeMap(options.src).then(map => {
  32       cache.psModuleMap = map;
  33       return cache.psModuleMap;
  34     });
  35   }
  36   else {
  37     return PsModuleMap.makeMapEntry(filePurs).then(result => {
  38       const map = Object.assign(cache.psModuleMap, result);
  39
  40       cache.psModuleMap = map;
  41
  42       return cache.psModuleMap;
  43     });
  44   }
  45 }
  46
  47  // Reference the bundle.
  48 function makeBundleJS(psModule) {
  49   const bundleOutput = psModule.options.bundleOutput;
  50
  51   const name = psModule.name;
  52
  53   const srcDir = psModule.srcDir;
  54
  55   const escaped = jsStringEscape(path.relative(srcDir, bundleOutput));
  56
  57   const result = `module.exports = require("${escaped}")["${name}"]`;
  58
  59   return result;
  60 }
  61
  62 // Replace require paths to output files generated by psc with paths
  63 // to purescript sources, which are then also run through this loader.
  64 // Additionally, the imports replaced are tracked so that in the event
  65 // the compiler fails to compile the PureScript source, we can tack on
  66 // any new imports in order to allow webpack to watch the new files
  67 // before they have been successfully compiled.
  68 function makeJS(psModule, psModuleMap, js) {
  69   const requireRE = /require\(['"]\.\.\/([\w\.]+)['"]\)/g;
  70
  71   const foreignRE = /require\(['"]\.\/foreign['"]\)/g;
  72
  73   const name = psModule.name;
  74
  75   const imports = psModuleMap[name].imports;
  76
  77   var replacedImports = [];
  78
  79   const result = js
  80     .replace(requireRE, (m, p1) => {
  81       const moduleValue = psModuleMap[p1];
  82
  83       if (!moduleValue) {
  84         debug('module %s was not found in the map, replacing require with null', p1);
  85
  86         return 'null';
  87       }
  88       else {
  89         const escapedPath = jsStringEscape(moduleValue.src);
  90
  91         replacedImports.push(p1);
  92
  93         return `require("${escapedPath}")`;
  94       }
  95     })
  96     .replace(foreignRE, () => {
  97       const escapedPath = jsStringEscape(psModuleMap[name].ffi);
  98
  99       return `require("${escapedPath}")`;
 100     })
 101   ;
 102
 103   const additionalImports = difference(imports, replacedImports);
 104
 105   if (additionalImports.length) {
 106     debugVerbose('additional imports for %s: %o', name, additionalImports);
 107   }
 108
 109   const additionalImportsResult = additionalImports.map(import_ => {
 110     const moduleValue = psModuleMap[import_];
 111
 112     if (!moduleValue) {
 113       debug('module %s was not found in the map, skipping require', import_);
 114
 115       return null;
 116     }
 117     else {
 118       const escapedPath = jsStringEscape(moduleValue.src);
 119
 120       return `var ${import_.replace(/\./g, '_')} = require("${escapedPath}")`;
 121     }
 122   }).filter(a => a !== null).join('\n');
 123
 124   const result_ = result + (additionalImports.length ? '\n' + additionalImportsResult : '');
 125
 126   return result_;
 127 }
 128
 129 module.exports = function toJavaScript(psModule) {
 130   const options = psModule.options;
 131
 132   const cache = psModule.cache;
 133
 134   const bundlePath = path.resolve(options.bundleOutput);
 135
 136   const jsPath = options.bundle ? bundlePath : psModule.jsPath;
 137
 138   const js = fs.readFileAsync(jsPath, 'utf8').catch(() => '');
 139
 140   const psModuleMap = updatePsModuleMap(psModule);
 141
 142   debugVerbose('loading JavaScript for %s', psModule.name);
 143
 144   return Promise.props({js: js, psModuleMap: psModuleMap}).then(result =>
 145     options.bundle ?
 146       makeBundleJS(psModule) :
 147       makeJS(psModule, result.psModuleMap, result.js)
 148   );
 149 };