Method must be called after React Context render - reactjs

Question

I've encountered an issue while using React Context. I use something like this to get the selected answer from the context:
const [selectedAnswer, setSelectedAnswer] = React.useState<boolean>(
isSelectedAnswer()
);
function isSelectedAnswer(): boolean {
return QuestionContext!
.getAnswers()
[QuestionContext!.getQuestionIndex(heading)].find(
({ name, value }) => name === heading && value === true
)
? true
: false;
}
But I receive a strange error:
TypeError: this.state.questions.find(...) is undefined
While typeof this.state.questions.find is function, obviously.
I believe the issue is happening, because the QuestionContext's React Component, and in the useState function it's not ready declared. I've used Profiler function, with onRender callback, but I realised that the Profiler function won't be a good candidate for that type of error. But yeah, it worked fine. Anyone knows how to fix that issue?
EDIT: Here's the Context code, which is returning error with the state.
import React, { Component } from "react";
import {
Question,
Questions,
Answers,
Answer,
ParsedAnswer,
Preset,
Presets,
} from "../../typings";
import QuestionsContext from "../QuestionsContext";
import questions from "../../data/questions";
import presets from "../../data/presets";
type QuestionsContextProviderProps = {
children: any;
};
export type QuestionsContextProvidedState = {
questions: Questions;
presets: Presets;
categories: string[];
answers: Answers;
selectedPreset: Preset | null;
getPresets: () => Presets;
getPresetForQuestion: (
questionCategoryIndex: number,
questionIndex: number
) => string;
setPreset: (preset: Preset) => void;
setPresetsInAnswers: (preset: Preset) => void;
getSelectedPreset: () => Preset | null;
getQuestions: () => Questions;
getFieldNameCategory: (fieldName: string) => string;
getQuestionIndex: (fieldName: string) => number;
getQuestionsFromIndex: (index: number) => Question[];
getAnswers: () => Answers;
sendNewAnswer: (
questionIndex: number,
fieldName: string,
answer: string | boolean
) => void | boolean | string;
parseAnswers: () => string;
};
export default class QuestionsContextProvider extends Component<
QuestionsContextProviderProps,
QuestionsContextProvidedState
> {
public readonly state: QuestionsContextProvidedState = {
questions: questions,
presets: presets,
categories: [],
answers: [],
selectedPreset: null,
getPresets: this.getPresets.bind(this),
getPresetForQuestion: this.getPresetForQuestion.bind(this),
setPreset: this.setPreset.bind(this),
setPresetsInAnswers: this.setPresetsInAnswers.bind(this),
getSelectedPreset: this.getSelectedPreset.bind(this),
getQuestions: this.getQuestions.bind(this),
getFieldNameCategory: this.getFieldNameCategory.bind(this),
getQuestionIndex: this.getQuestionIndex.bind(this),
getQuestionsFromIndex: this.getQuestionsFromIndex.bind(this),
getAnswers: this.getAnswers.bind(this),
sendNewAnswer: this.sendNewAnswer.bind(this),
parseAnswers: this.parseAnswers.bind(this),
};
constructor(props: any) {
super(props);
const endingAnswersArray = this.state.answers;
const endingCatagoriesArray = this.state.categories;
const alreadyUsedKeys: string[] = [];
this.state.questions.forEach(({ key }) => {
if (alreadyUsedKeys.find((value) => value === key)) return;
endingAnswersArray.push([]);
endingCatagoriesArray.push(key);
alreadyUsedKeys.push(key);
});
this.state.answers = endingAnswersArray;
this.state.categories = endingCatagoriesArray;
}
public getPresets(): Presets {
return this.state.presets;
}
public getPresetForQuestion(
questionCategoryIndex: number,
questionIndex: number,
preset?: Preset
): string {
return this.state.questions[questionCategoryIndex].values[questionIndex]
.presets[preset || this.state.selectedPreset!];
}
public setPreset(preset: Preset): void {
this.setState({
selectedPreset: preset,
});
}
private getDefaultValueForQuestion(
questionCategoryIndex: number,
questionIndex: number
): string {
return this.state.questions[questionCategoryIndex].values[questionIndex]
.defaultValue;
}
public setPresetsInAnswers(preset: Preset): void {
this.state.categories.forEach((_, key) => {
this.state.questions.forEach(({ values }, idx) => {
values.forEach(({ name }, questionKey) => {
const selectedPreset = this.getPresetForQuestion(
idx,
questionKey,
preset
);
let newPreset: string | boolean = selectedPreset;
if (selectedPreset === "true") newPreset = true;
if (selectedPreset === "false") newPreset = false;
if (
selectedPreset === this.getDefaultValueForQuestion(idx, questionKey)
)
return;
this.sendNewAnswer(key, name, newPreset);
});
});
});
}
public getSelectedPreset(): Preset | null {
return this.state.selectedPreset;
}
public getQuestions(): Questions {
return this.state.questions;
}
public getFieldNameCategory(fieldName: string): string {
return this.state.questions.find(({ values }) =>
values.find(({ name }) => name === fieldName)
)!.key;
}
public getQuestionIndex(fieldName: string): number {
return this.state.categories.findIndex(
(value) => value === this.getFieldNameCategory(fieldName)
);
}
public getQuestionsFromIndex(index: number): Question[] {
return this.state.questions[index].values;
}
public getAnswers(): Answers {
return this.state.answers;
}
public sendNewAnswer(
questionIndex: number,
fieldName: string,
answer: string | boolean
): void | boolean | string {
const alreadyAnsweredField = this.state.answers[questionIndex].find(
({ name }) => name === fieldName
);
if (alreadyAnsweredField) {
return (alreadyAnsweredField.value = answer);
}
const endingAnswersField = this.state.answers;
endingAnswersField[questionIndex].push({
name: fieldName,
value: answer,
});
this.setState({
answers: endingAnswersField,
});
}
public parseAnswers(): string {
const parsedAnswer: ParsedAnswer = {};
this.state.categories.forEach((value, key) => {
parsedAnswer[value] = {};
this.getAnswers()[key].forEach((answer: Answer) => {
parsedAnswer[value][answer.name] = answer.value;
});
});
return JSON.stringify(parsedAnswer, null, 2);
}
public render() {
return (
<QuestionsContext.Provider value={this.state}>
{this.props.children}
</QuestionsContext.Provider>
);
}
}