Angular 5 typescript issue

[Antony-augusta]

while running a comment "ng serve" its showing error.

ERROR in node_modules/api-ai-javascript/ts/Request/TTSRequest.ts(18,37): error TS2339: Property 'AudioContext' does not exist on type 'Window'. node_modules/api-ai-javascript/ts/Request/TTSRequest.ts(18,53): error TS2304: Cannot find name 'webkitAudioContext'. node_modules/api-ai-javascript/ts/Stream/Processors.ts(7,16): error TS2339: Property 'AudioContext' does not exist on type 'Window'. node_modules/api-ai-javascript/ts/Stream/Processors.ts(7,38): error TS2339: Property 'AudioContext' does not exist on type 'Window'. node_modules/api-ai-javascript/ts/Stream/Processors.ts(7,54): error TS2304: Cannot find name 'webkitAudioContext'. node_modules/api-ai-javascript/ts/Stream/StreamClient.ts(60,20): error TS2339: Property 'AudioContext' does not exist on type 'Window'. node_modules/api-ai-javascript/ts/Stream/StreamClient.ts(60,42): error TS2339: Property 'AudioContext' does not exist on type 'Window'. node_modules/api-ai-javascript/ts/Stream/StreamClient.ts(60,58): error TS2304: Cannot find name 'webkitAudioContext'. node_modules/api-ai-javascript/ts/Stream/StreamClient.ts(62,53): error TS2339: Property 'webkitGetUserMedia' does not exist on type 'Navigator'. node_modules/api-ai-javascript/ts/Stream/StreamClient.ts(62,85): error TS2339: Property 'mozGetUserMedia' does not exist on type 'Navigator'. node_modules/api-ai-javascript/ts/XhrRequest.ts(105,19): error TS2304: Cannot find name 'ActiveXObject'. node_modules/api-ai-javascript/ts/XhrRequest.ts(106,19): error TS2304: Cannot find name 'ActiveXObject'. node_modules/api-ai-javascript/ts/XhrRequest.ts(107,19): error TS2304: Cannot find name 'ActiveXObject'.

[TudorIoanMarin]

Rolled back to version beta-19 and now I have this issue as well.