TypeError: Promise is not a constructor

[abmnukmr]

TypeError: Promise is not a constructor
at Function. (http://localhost:8100/build/main.js:8876:19)
at Function.allDbs (http://localhost:8100/build/main.js:8856:16)
at ChatlistPagePage.webpackJsonp.566.ChatlistPagePage.loadi (http://localhost:8100/build/main.js:4482:76)
at ChatlistPagePage.webpackJsonp.566.ChatlistPagePage.ionViewDidEnter (http://localhost:8100/build/main.js:4566:14)
at ViewController._lifecycle (http://localhost:8100/build/vendor.js:27629:33)
at ViewController._didEnter (http://localhost:8100/build/vendor.js:27538:14)
at NavControllerBase._didEnter (http://localhost:8100/build/vendor.js:63799:18)
at NavControllerBase._transitionFinish (http://localhost:8100/build/vendor.js:63630:22)
at http://localhost:8100/build/vendor.js:63616:26
at t.invoke (http://localhost:8100/build/polyfills.js:3:14976)