Property 'observable' does not exist on type 'SymbolConstructor'.

Where

TS 使用 rxjs報錯

"dependencies": {
    "core-js": "^3.6.4",
    "register-service-worker": "^1.6.2",
    "rxjs": "^6.5.4",
    "vue": "^2.6.11",
    "vue-class-component": "^7.2.2",
    "vue-property-decorator": "^8.3.0",
    "vue-router": "^3.1.5",
    "vuex": "^3.1.2"
  },
  "devDependencies": {
    "@types/jest": "^24.0.19",
    "@typescript-eslint/eslint-plugin": "^2.18.0",
    "@typescript-eslint/parser": "^2.18.0",
    "@vue/cli-plugin-babel": "~4.2.0",
    "@vue/cli-plugin-eslint": "~4.2.0",
    "@vue/cli-plugin-pwa": "~4.2.0",
    "@vue/cli-plugin-router": "~4.2.0",
    "@vue/cli-plugin-typescript": "~4.2.0",
    "@vue/cli-plugin-unit-jest": "~4.2.0",
    "@vue/cli-plugin-vuex": "~4.2.0",
    "@vue/cli-service": "~4.2.0",
    "@vue/eslint-config-typescript": "^5.0.1",
    "@vue/test-utils": "1.0.0-beta.31",
    "eslint": "^6.7.2",
    "eslint-plugin-vue": "^6.1.2",
    "typescript": "~3.7.5",
    "vue-template-compiler": "^2.6.11"
  },

import { ajax } from "rxjs/ajax";

How

相關聲明文件是 import rxjs順便導入的
只使用了部分引入 自然會報錯

Solution

import "rxjs"
import { ajax } from "rxjs/ajax";

Reference

查看這個issue