react-intl: redundant console output suppressor

filter.js

// this filter suppress react-intl's redundant console output while not in production
class ErrorConsoleFilter {
    constructor(disabledValue) {
        this.disabledValue = disabledValue;
        this.originalConsoleError = console.error;              // eslint-disable-line no-console
        this.outputHandler = this.outputHandler.bind(this);
        console.error = this.outputHandler;                     // eslint-disable-line no-console
    }
    outputHandler(...args) {
        if (args[0].indexOf(this.disabledValue) === 0) return;
        this.originalConsoleError.call(console, ...args);
    }
}

export const filterRedundandMessages = (on) => {
    if (on) return new ErrorConsoleFilter('[React Intl] Missing message:');
    return null;
};
export const getProductionState = () => process.env.NODE_ENV === 'production';

filterRedundandMessages(!getProductionState);

filter.unit.spec.js

import { expect } from 'chai';

import { filterRedundandMessages, getProductionState } from './filter';

describe('Unit: i18n.config', () => {
    it('getProductionState', () => {
        expect(getProductionState()).to.be.eql(false);
    });
    describe('Redundant message filter', () => {
        const consoleFilter = filterRedundandMessages(true);
        let consoleOutput = '';
        let consoleOrigin = null;
        const consoleMock = (...args) => { consoleOutput = args; };

        before(() => {
            consoleOrigin = consoleFilter.originalConsoleError;
            consoleFilter.originalConsoleError = consoleMock;
        });

        after(() => {
            consoleFilter.originalConsoleError = consoleOrigin;
        });

        beforeEach(() => {
            consoleOutput = '';
        });

        it('disabled message', () => {
            const disabledMessage = '[React Intl] Missing message: disabled message';
            console.error(disabledMessage);                             // eslint-disable-line no-console
            expect(consoleOutput).to.be.eql('');
        });
        it('enabled message', () => {
            const enabledMessage = 'enabled message';
            console.error(enabledMessage);                              // eslint-disable-line no-console
            expect(consoleOutput).to.be.eql([enabledMessage]);
        });
    });
});