Angular 等待方法完成，然后再设置值

我有一个正在调用的方法。在方法完成并得到响应之后，我想给变量赋值。目前我不确定如何在设置值之前等待端点调用完成

这是我的密码

成分ngOninit

//在上述行完成后，我只应继续下面的操作

除了使用设置时间，还有其他方法吗

  public cacheDropdownOptions() {
    this._subscriptions.push(this.getRoles().subscribe((resp) => {
      if (resp) {
        const rolesArr = Object.entries(resp).map(x => ({ value: x[0], label: x[1].toString() }));
        localStorage.setItem('roles', JSON.stringify(rolesArr));
      } else {
        this._errorService.openErrorPopup('An error occured while extracting the roles.');
      }
    }, (error) => {
      this._errorService.openErrorPopup('An error occured while extracting the roles.');
    }));

    const medicalPlansArr = medicalAidPlans.map(x => ({ label: x.name, value: x.id }));

    this._subscriptions.push(this.getLookups().subscribe((resp) => {
      if (resp) {

        localStorage.setItem('medicalPlans', JSON.stringify(medicalPlansArr));

        if (resp.genders) {
          const genderArr = Object.entries(resp.genders).map(x => ({ value: x[0], label: x[1].toString() }));
          localStorage.setItem('genders', JSON.stringify(genderArr));
        }
        if (resp.races) {
          const racesArr = Object.entries(resp.races).map(x => ({ value: x[0], label: x[1].toString() }));
          localStorage.setItem('races', JSON.stringify(racesArr));
        }
        if (resp.titles) {
          const titlesArr = Object.entries(resp.titles).map(x => ({ value: x[0], label: x[1].toString() }));
          localStorage.setItem('titles', JSON.stringify(titlesArr));
        }
        if (resp.maritalStatus) {
          const maritalStatusArr = Object.entries(resp.maritalStatus).map(x => ({ value: x[0], label: x[1].toString() }));
          localStorage.setItem('maritalStatus', JSON.stringify(maritalStatusArr));
        }
        if (resp.nationality) {
          const nationalityArr = Object.entries(resp.nationality).map(x => ({ value: x[0], label: x[1].toString() }));
          localStorage.setItem('nationality', JSON.stringify(nationalityArr));
        }
        if (resp.identityTypes) {
          const identityTypesArr = Object.entries(resp.identityTypes).map(x => ({ value: x[0], label: x[1].toString() }));
          localStorage.setItem('identityTypes', JSON.stringify(identityTypesArr));
        }
        if (resp.companyTypes) {
          const companyTypeArray = Object.entries(resp.companyTypes).map(x => ({ value: x[0], label: x[1].toString() }));
          localStorage.setItem('companyTypes', JSON.stringify(companyTypeArray));
        }
        if (resp.industries) {
          const industryArray = Object.entries(resp.industries).map(x => ({ value: x[0], label: x[1].toString() }));
          localStorage.setItem('industry', JSON.stringify(industryArray));
        }
        if (resp.fileTypes) {
          const fileTypesArr = Object.entries(resp.fileTypes).map(x => ({ value: x[0], label: x[1].toString() }));
          localStorage.setItem('fileTypes', JSON.stringify(fileTypesArr));
        }
        if (resp.userDocumentCategories) {
          const documentCategoriesArray = Object.entries(resp.userDocumentCategories).map(x => ({ value: x[0], label: x[1].toString() }));
          localStorage.setItem('documentCategories', JSON.stringify(documentCategoriesArray));
        }
        if (resp.reasonExtend) {
          const reasonExtendArr = Object.entries(resp.reasonExtend).map(x => ({ value: x[0], label: x[1].toString() }));
          localStorage.setItem('extendReasons', JSON.stringify(reasonExtendArr));
        }
        if (resp.reasonRescind) {
          const reasonRescindArr = Object.entries(resp.reasonRescind).map(x => ({ value: x[0], label: x[1].toString() }));
          localStorage.setItem('rescindReasons', JSON.stringify(reasonRescindArr));
        }
        if (resp.sources) {
          const savingsSourcesArr = Object.entries(resp.sources).map(x => ({ value: x[0], label: x[1].toString() }));
          localStorage.setItem('savingsSources', JSON.stringify(savingsSourcesArr));
        }

        localStorage.setItem('contentSet', 'true');
        this.lookupsCached.next(true);

      } else {
        this._errorService.openErrorPopup('An error occured while extracting the lookups.');
      }
    }, (error) => {
      this._errorService.openErrorPopup('An error occured while extracting the lookups.');
    }));
  }

---

您可以将基本承诺与async/await一起使用

async ngOnInit() {

    await this.cacheDropdownOptions();


    this.nationalities = JSON.parse(localStorage.getItem('nationality'));
    this.titles = JSON.parse(localStorage.getItem('titles'));
    this.idDocumentTypes = JSON.parse(localStorage.getItem('identityTypes'));
    this.genders = JSON.parse(localStorage.getItem('genders'));
  }

  async cacheDropdownOptions() {
    .. use subscription
  }
}

---

发布您的cacheDropdownOptions函数代码如果该方法返回一个承诺，您可以只使用承诺链来确保它在之后发生。

  public cacheDropdownOptions() {
    this._subscriptions.push(this.getRoles().subscribe((resp) => {
      if (resp) {
        const rolesArr = Object.entries(resp).map(x => ({ value: x[0], label: x[1].toString() }));
        localStorage.setItem('roles', JSON.stringify(rolesArr));
      } else {
        this._errorService.openErrorPopup('An error occured while extracting the roles.');
      }
    }, (error) => {
      this._errorService.openErrorPopup('An error occured while extracting the roles.');
    }));

    const medicalPlansArr = medicalAidPlans.map(x => ({ label: x.name, value: x.id }));

    this._subscriptions.push(this.getLookups().subscribe((resp) => {
      if (resp) {

        localStorage.setItem('medicalPlans', JSON.stringify(medicalPlansArr));

        if (resp.genders) {
          const genderArr = Object.entries(resp.genders).map(x => ({ value: x[0], label: x[1].toString() }));
          localStorage.setItem('genders', JSON.stringify(genderArr));
        }
        if (resp.races) {
          const racesArr = Object.entries(resp.races).map(x => ({ value: x[0], label: x[1].toString() }));
          localStorage.setItem('races', JSON.stringify(racesArr));
        }
        if (resp.titles) {
          const titlesArr = Object.entries(resp.titles).map(x => ({ value: x[0], label: x[1].toString() }));
          localStorage.setItem('titles', JSON.stringify(titlesArr));
        }
        if (resp.maritalStatus) {
          const maritalStatusArr = Object.entries(resp.maritalStatus).map(x => ({ value: x[0], label: x[1].toString() }));
          localStorage.setItem('maritalStatus', JSON.stringify(maritalStatusArr));
        }
        if (resp.nationality) {
          const nationalityArr = Object.entries(resp.nationality).map(x => ({ value: x[0], label: x[1].toString() }));
          localStorage.setItem('nationality', JSON.stringify(nationalityArr));
        }
        if (resp.identityTypes) {
          const identityTypesArr = Object.entries(resp.identityTypes).map(x => ({ value: x[0], label: x[1].toString() }));
          localStorage.setItem('identityTypes', JSON.stringify(identityTypesArr));
        }
        if (resp.companyTypes) {
          const companyTypeArray = Object.entries(resp.companyTypes).map(x => ({ value: x[0], label: x[1].toString() }));
          localStorage.setItem('companyTypes', JSON.stringify(companyTypeArray));
        }
        if (resp.industries) {
          const industryArray = Object.entries(resp.industries).map(x => ({ value: x[0], label: x[1].toString() }));
          localStorage.setItem('industry', JSON.stringify(industryArray));
        }
        if (resp.fileTypes) {
          const fileTypesArr = Object.entries(resp.fileTypes).map(x => ({ value: x[0], label: x[1].toString() }));
          localStorage.setItem('fileTypes', JSON.stringify(fileTypesArr));
        }
        if (resp.userDocumentCategories) {
          const documentCategoriesArray = Object.entries(resp.userDocumentCategories).map(x => ({ value: x[0], label: x[1].toString() }));
          localStorage.setItem('documentCategories', JSON.stringify(documentCategoriesArray));
        }
        if (resp.reasonExtend) {
          const reasonExtendArr = Object.entries(resp.reasonExtend).map(x => ({ value: x[0], label: x[1].toString() }));
          localStorage.setItem('extendReasons', JSON.stringify(reasonExtendArr));
        }
        if (resp.reasonRescind) {
          const reasonRescindArr = Object.entries(resp.reasonRescind).map(x => ({ value: x[0], label: x[1].toString() }));
          localStorage.setItem('rescindReasons', JSON.stringify(reasonRescindArr));
        }
        if (resp.sources) {
          const savingsSourcesArr = Object.entries(resp.sources).map(x => ({ value: x[0], label: x[1].toString() }));
          localStorage.setItem('savingsSources', JSON.stringify(savingsSourcesArr));
        }

        localStorage.setItem('contentSet', 'true');
        this.lookupsCached.next(true);

      } else {
        this._errorService.openErrorPopup('An error occured while extracting the lookups.');
      }
    }, (error) => {
      this._errorService.openErrorPopup('An error occured while extracting the lookups.');
    }));
  }

async ngOnInit() {

    await this.cacheDropdownOptions();


    this.nationalities = JSON.parse(localStorage.getItem('nationality'));
    this.titles = JSON.parse(localStorage.getItem('titles'));
    this.idDocumentTypes = JSON.parse(localStorage.getItem('identityTypes'));
    this.genders = JSON.parse(localStorage.getItem('genders'));
  }

  async cacheDropdownOptions() {
    .. use subscription
  }
}