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"),a("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// 2")]),t._v("\n"),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),a("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n")])])]),a("p",[t._v("So, looking at the above code, we are writing async code that looks like it's "),a("code",[t._v("blocking")]),t._v(" (the yield statements wait for 100ms and then continue execution), but it's actually "),a("code",[t._v("waiting")]),t._v(". The "),a("code",[t._v("pause")]),t._v(" and "),a("code",[t._v("resume")]),t._v(" property of generator allows us to do this amazing trick.")]),t._v(" "),a("h3",{attrs:{id:"how-does-it-work"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#how-does-it-work"}},[t._v("#")]),t._v(" How does it work ?")]),t._v(" "),a("p",[t._v("The spawn function uses "),a("code",[t._v("yield promise")]),t._v(" to PULL the promise state from the generator, waits till the promise is resolved, and PUSHes the resolved value back to the generator so it can consume it.")]),t._v(" "),a("h3",{attrs:{id:"use-it-now"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#use-it-now"}},[t._v("#")]),t._v(" Use it now")]),t._v(" "),a("p",[t._v("So, with generators and spawn function, you can clean up all your async code in NodeJS to look and feel like it's synchronous. This will make debugging easy. 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But you can use them today in ES2015/ES6 using the spawn function defined in the libraries - taskjs, co, or bluebird")]),t._v(" "),a("h4",{attrs:{id:"syntax"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#syntax"}},[t._v("#")]),t._v(" Syntax")]),t._v(" "),a("ul",[a("li",[t._v("function* name(parameters) { yield value; return value }")]),t._v(" "),a("li",[t._v("generator = name(arguments)")]),t._v(" "),a("li",[t._v("{ value, done } = generator.next(value)")]),t._v(" "),a("li",[t._v("{ value, done } = generator.return(value)")]),t._v(" "),a("li",[t._v("generator.throw(error)")])]),t._v(" "),a("h4",{attrs:{id:"remarks"}},[a("a",{staticClass:"header-anchor",attrs:{href:"#remarks"}},[t._v("#")]),t._v(" Remarks")]),t._v(" "),a("p",[t._v("Generator functions are a feature introduced as part of the ES 2015 specification and are not available in all browsers. They are also fully supported in Node.js as of "),a("code",[t._v("v6.0")]),t._v(". 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