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nathggns revised this gist
May 27, 2015 . 1 changed file with 17 additions and 2 deletions.There are no files selected for viewing
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters. Learn more about bidirectional Unicode charactersOriginal file line number Diff line number Diff line change @@ -1,20 +1,35 @@ function await(generatorFunction) { let gen = generatorFunction(); /** * @param {any?} err The error to throw in the generator, where yield was last called. * @param {any?} result The result to pass to the genarator for the last call to yield */ function next(err, result) { // If the last promise that was yielded was rejected, // trigger an error inside the generator where yield was last called if (err) { gen.throw( // Make sure that the error we're passing is actually an error and not just a string err instanceof Error ? err : new Error(err) ); } // Get the next promise from the generator let nextResult = gen.next( result ); let value = nextResult.value; // If we're done with the generator, no need to keep going. if (nextResult.done) { return; } value.then( // We have a value, call next again to pass it back into the generator and keep going result => next(null, result), // We have an error, throw it in the generator e => next(e) ); } -
nathggns created this gist
May 27, 2015 .There are no files selected for viewing
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters. Learn more about bidirectional Unicode charactersOriginal file line number Diff line number Diff line change @@ -0,0 +1,44 @@ function await(generatorFunction) { let gen = generatorFunction(); function next(err, result) { if (err) { gen.throw(err instanceof Error ? err : new Error(err)); } let nextResult = gen.next(result); let value = nextResult.value; if (nextResult.done) { return; } value.then( result => next(null, result), e => next(e) ); } next(); } function generateRandomNumber() { return new Promise(resolve => setTimeout(() => resolve(Math.random()), 2000)); } function makeError() { return new Promise((r, reject) => reject('Some error')); } await(function*() { try { console.log('Starting random number generator'); console.log('Random number is', yield generateRandomNumber()); console.log('Starting another random number generator'); console.log('Another random number is', yield generateRandomNumber()); console.log('Throwing error'); yield makeError(); } catch (e) { console.error('Caught error', e); } });