lib/to-javascript.js

   1 'use strict';
   2
   3 var Promise = require('bluebird');
   4
   5 var fs = Promise.promisifyAll(require('fs'));
   6
   7 var path = require('path');
   8
   9 var jsStringEscape = require('js-string-escape');
  10
  11 var difference = require('lodash.difference');
  12
  13 var debug_ = require('debug');
  14
  15 var debug = debug_('purs-loader');
  16
  17 var debugVerbose = debug_('purs-loader:verbose');
  18
  19 var PsModuleMap = require('./purs-module-map');
  20
  21 function updatePsModuleMap(psModule) {
  22   var options = psModule.options;
  23
  24   var cache = psModule.cache;
  25
  26   var 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   } else {
  35     debugVerbose('module mapping exists - updating module map for %s', filePurs);
  36
  37     cache.psModuleMap = cache.psModuleMap.then(function (psModuleMap) {
  38       return PsModuleMap.makeMapEntry(filePurs).then(function (result) {
  39         var map = Object.assign(psModuleMap, result);
  40
  41         return map;
  42       });
  43     });
  44
  45     return cache.psModuleMap;
  46   }
  47 }
  48
  49 // Reference the bundle.
  50 function makeBundleJS(psModule) {
  51   var bundleOutput = psModule.options.bundleOutput;
  52
  53   var name = psModule.name;
  54
  55   var srcDir = psModule.srcDir;
  56
  57   var escaped = jsStringEscape(path.relative(srcDir, bundleOutput));
  58
  59   var result = 'module.exports = require("' + escaped + '")["' + name + '"]';
  60
  61   return Promise.resolve(result);
  62 }
  63
  64 // Replace require paths to output files generated by psc with paths
  65 // to purescript sources, which are then also run through this loader.
  66 // Additionally, the imports replaced are tracked so that in the event
  67 // the compiler fails to compile the PureScript source, we can tack on
  68 // any new imports in order to allow webpack to watch the new files
  69 // before they have been successfully compiled.
  70 function makeJS(psModule, psModuleMap, js) {
  71   var requireRE = /require\(['"]\.\.\/([\w\.]+)(?:\/index\.js)?['"]\)/g;
  72
  73   var foreignRE = /require\(['"]\.\/foreign(?:\.js)?['"]\)/g;
  74
  75   var name = psModule.name;
  76
  77   var imports = psModuleMap[name].imports;
  78
  79   var replacedImports = [];
  80
  81   var result = js.replace(requireRE, function (m, p1) {
  82     var moduleValue = psModuleMap[p1];
  83
  84     if (!moduleValue) {
  85       debug('module %s was not found in the map, replacing require with null', p1);
  86
  87       return 'null';
  88     } else {
  89       var escapedPath = jsStringEscape(moduleValue.src);
  90
  91       replacedImports.push(p1);
  92
  93       return 'require("' + escapedPath + '")';
  94     }
  95   }).replace(foreignRE, function () {
  96     var escapedPath = jsStringEscape(psModuleMap[name].ffi);
  97
  98     return 'require("' + escapedPath + '")';
  99   });
 100
 101   var additionalImports = difference(imports, replacedImports);
 102
 103   if (!additionalImports.length) {
 104     return Promise.resolve(result);
 105   } else {
 106     debug('rebuilding module map due to additional imports for %s: %o', name, additionalImports);
 107
 108     psModule.cache.psModuleMap = null;
 109
 110     return updatePsModuleMap(psModule).then(function (updatedPsModuleMap) {
 111       var additionalImportsResult = additionalImports.map(function (import_) {
 112         var moduleValue = updatedPsModuleMap[import_];
 113
 114         if (!moduleValue) {
 115           debug('module %s was not found in the map, skipping require', import_);
 116
 117           return null;
 118         } else {
 119           var escapedPath = jsStringEscape(moduleValue.src);
 120
 121           return 'var ' + import_.replace(/\./g, '_') + ' = require("' + escapedPath + '")';
 122         }
 123       }).filter(function (a) {
 124         return a !== null;
 125       }).join('\n');
 126
 127       return result + '\n' + additionalImportsResult;
 128     });
 129   }
 130 }
 131
 132 module.exports = function toJavaScript(psModule) {
 133   var options = psModule.options;
 134
 135   var cache = psModule.cache;
 136
 137   var bundlePath = path.resolve(options.bundleOutput);
 138
 139   var jsPath = options.bundle ? bundlePath : psModule.jsPath;
 140
 141   var js = fs.readFileAsync(jsPath, 'utf8').catch(function () {
 142     return '';
 143   });
 144
 145   var psModuleMap = updatePsModuleMap(psModule);
 146
 147   debugVerbose('loading JavaScript for %s', psModule.name);
 148
 149   return Promise.props({ js: js, psModuleMap: psModuleMap }).then(function (result) {
 150     return options.bundle ? makeBundleJS(psModule) : makeJS(psModule, result.psModuleMap, result.js);
 151   });
 152 };