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     debugVerbose('module mapping does not exist - making a new module map');
  30
  31     cache.psModuleMap = PsModuleMap.makeMap(options.src);
  32
  33     return cache.psModuleMap;
  34   }
  35   else {
  36     debugVerbose('module mapping exists - updating module map for %s', filePurs);
  37
  38     cache.psModuleMap = cache.psModuleMap.then(psModuleMap =>
  39       PsModuleMap.makeMapEntry(filePurs).then(result => {
  40         const map = Object.assign(psModuleMap, result);
  41
  42         return map;
  43       })
  44     );
  45
  46     return cache.psModuleMap;
  47   }
  48 }
  49
  50  // Reference the bundle.
  51 function makeBundleJS(psModule) {
  52   const bundleOutput = psModule.options.bundleOutput;
  53
  54   const name = psModule.name;
  55
  56   const srcDir = psModule.srcDir;
  57
  58   const escaped = jsStringEscape(path.relative(srcDir, bundleOutput));
  59
  60   const result = `module.exports = require("${escaped}")["${name}"]`;
  61
  62   return Promise.resolve(result);
  63 }
  64
  65 // Replace require paths to output files generated by psc with paths
  66 // to purescript sources, which are then also run through this loader.
  67 // Additionally, the imports replaced are tracked so that in the event
  68 // the compiler fails to compile the PureScript source, we can tack on
  69 // any new imports in order to allow webpack to watch the new files
  70 // before they have been successfully compiled.
  71 function makeJS(psModule, psModuleMap, js) {
  72   const requireRE = /require\(['"]\.\.\/([\w\.]+)(?:\/index\.js)?['"]\)/g;
  73
  74   const foreignRE = /require\(['"]\.\/foreign(?:\.js)?['"]\)/g;
  75
  76   const name = psModule.name;
  77
  78   const imports = psModuleMap[name].imports;
  79
  80   var replacedImports = [];
  81
  82   const result = js
  83     .replace(requireRE, (m, p1) => {
  84       const moduleValue = psModuleMap[p1];
  85
  86       if (!moduleValue) {
  87         debug('module %s was not found in the map, replacing require with null', p1);
  88
  89         return 'null';
  90       }
  91       else {
  92         const escapedPath = jsStringEscape(moduleValue.src);
  93
  94         replacedImports.push(p1);
  95
  96         return `require("${escapedPath}")`;
  97       }
  98     })
  99     .replace(foreignRE, () => {
 100       const escapedPath = jsStringEscape(psModuleMap[name].ffi);
 101
 102       return `require("${escapedPath}")`;
 103     })
 104   ;
 105
 106   const additionalImports = difference(imports, replacedImports);
 107
 108   if (!additionalImports.length) {
 109     return Promise.resolve(result);
 110   }
 111   else {
 112     debug('rebuilding module map due to additional imports for %s: %o', name, additionalImports);
 113
 114     psModule.cache.psModuleMap = null;
 115
 116     return updatePsModuleMap(psModule).then(updatedPsModuleMap => {
 117       const additionalImportsResult = additionalImports.map(import_ => {
 118         const moduleValue = updatedPsModuleMap[import_];
 119
 120         if (!moduleValue) {
 121           debug('module %s was not found in the map, skipping require', import_);
 122
 123           return null;
 124         }
 125         else {
 126           const escapedPath = jsStringEscape(moduleValue.src);
 127
 128           return `var ${import_.replace(/\./g, '_')} = require("${escapedPath}")`;
 129         }
 130       }).filter(a => a !== null).join('\n');
 131
 132       return result + '\n' + additionalImportsResult;
 133     });
 134   }
 135 }
 136
 137 module.exports = function toJavaScript(psModule) {
 138   const options = psModule.options;
 139
 140   const cache = psModule.cache;
 141
 142   const bundlePath = path.resolve(options.bundleOutput);
 143
 144   const jsPath = options.bundle ? bundlePath : psModule.jsPath;
 145
 146   const js = fs.readFileAsync(jsPath, 'utf8').catch(() => '');
 147
 148   const psModuleMap = updatePsModuleMap(psModule);
 149
 150   debugVerbose('loading JavaScript for %s', psModule.name);
 151
 152   return Promise.props({js: js, psModuleMap: psModuleMap}).then(result =>
 153     options.bundle ?
 154       makeBundleJS(psModule) :
 155       makeJS(psModule, result.psModuleMap, result.js)
 156   );
 157 };