1 | ;
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2 |
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3 | Object.defineProperty(exports, "__esModule", {
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4 | value: true
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5 | });
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6 | exports.default = asyncify;
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7 |
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8 | var _initialParams = require('./internal/initialParams.js');
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9 |
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10 | var _initialParams2 = _interopRequireDefault(_initialParams);
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11 |
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12 | var _setImmediate = require('./internal/setImmediate.js');
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13 |
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14 | var _setImmediate2 = _interopRequireDefault(_setImmediate);
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15 |
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16 | var _wrapAsync = require('./internal/wrapAsync.js');
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17 |
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18 | function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
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19 |
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20 | /**
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21 | * Take a sync function and make it async, passing its return value to a
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22 | * callback. This is useful for plugging sync functions into a waterfall,
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23 | * series, or other async functions. Any arguments passed to the generated
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24 | * function will be passed to the wrapped function (except for the final
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25 | * callback argument). Errors thrown will be passed to the callback.
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26 | *
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27 | * If the function passed to `asyncify` returns a Promise, that promises's
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28 | * resolved/rejected state will be used to call the callback, rather than simply
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29 | * the synchronous return value.
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30 | *
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31 | * This also means you can asyncify ES2017 `async` functions.
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32 | *
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33 | * @name asyncify
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34 | * @static
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35 | * @memberOf module:Utils
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36 | * @method
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37 | * @alias wrapSync
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38 | * @category Util
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39 | * @param {Function} func - The synchronous function, or Promise-returning
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40 | * function to convert to an {@link AsyncFunction}.
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41 | * @returns {AsyncFunction} An asynchronous wrapper of the `func`. To be
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42 | * invoked with `(args..., callback)`.
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43 | * @example
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44 | *
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45 | * // passing a regular synchronous function
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46 | * async.waterfall([
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47 | * async.apply(fs.readFile, filename, "utf8"),
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48 | * async.asyncify(JSON.parse),
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49 | * function (data, next) {
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50 | * // data is the result of parsing the text.
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51 | * // If there was a parsing error, it would have been caught.
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52 | * }
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53 | * ], callback);
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54 | *
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55 | * // passing a function returning a promise
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56 | * async.waterfall([
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57 | * async.apply(fs.readFile, filename, "utf8"),
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58 | * async.asyncify(function (contents) {
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59 | * return db.model.create(contents);
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60 | * }),
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61 | * function (model, next) {
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62 | * // `model` is the instantiated model object.
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63 | * // If there was an error, this function would be skipped.
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64 | * }
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65 | * ], callback);
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66 | *
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67 | * // es2017 example, though `asyncify` is not needed if your JS environment
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68 | * // supports async functions out of the box
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69 | * var q = async.queue(async.asyncify(async function(file) {
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70 | * var intermediateStep = await processFile(file);
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71 | * return await somePromise(intermediateStep)
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72 | * }));
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73 | *
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74 | * q.push(files);
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75 | */
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76 | function asyncify(func) {
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77 | if ((0, _wrapAsync.isAsync)(func)) {
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78 | return function (...args /*, callback*/) {
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79 | const callback = args.pop();
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80 | const promise = func.apply(this, args);
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81 | return handlePromise(promise, callback);
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82 | };
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83 | }
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84 |
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85 | return (0, _initialParams2.default)(function (args, callback) {
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86 | var result;
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87 | try {
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88 | result = func.apply(this, args);
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89 | } catch (e) {
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90 | return callback(e);
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91 | }
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92 | // if result is Promise object
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93 | if (result && typeof result.then === 'function') {
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94 | return handlePromise(result, callback);
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95 | } else {
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96 | callback(null, result);
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97 | }
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98 | });
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99 | }
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100 |
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101 | function handlePromise(promise, callback) {
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102 | return promise.then(value => {
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103 | invokeCallback(callback, null, value);
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104 | }, err => {
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105 | invokeCallback(callback, err && (err instanceof Error || err.message) ? err : new Error(err));
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106 | });
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107 | }
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108 |
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109 | function invokeCallback(callback, error, value) {
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110 | try {
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111 | callback(error, value);
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112 | } catch (err) {
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113 | (0, _setImmediate2.default)(e => {
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114 | throw e;
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115 | }, err);
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116 | }
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117 | }
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118 | module.exports = exports.default; |
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