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