diff --git a/src/components/base/ItemIconBase.ts b/src/components/base/ItemIconBase.ts
index 58241129..ae10b11e 100644
--- a/src/components/base/ItemIconBase.ts
+++ b/src/components/base/ItemIconBase.ts
@@ -41,11 +41,11 @@ export function useItemIconBase(props: CommonIconProps) {
             iconId = iconId.toString();
         }
 
-        if (!ALL_ACCOUNT_ICONS[iconId as string]) {
+        if (!ALL_ACCOUNT_ICONS[iconId]) {
             return DEFAULT_ACCOUNT_ICON.icon;
         }
 
-        return ALL_ACCOUNT_ICONS[iconId as string].icon;
+        return ALL_ACCOUNT_ICONS[iconId].icon;
     }
 
     function getCategoryIcon(iconId: string | number): string {
@@ -53,11 +53,11 @@ export function useItemIconBase(props: CommonIconProps) {
             iconId = iconId.toString();
         }
 
-        if (!ALL_CATEGORY_ICONS[iconId as string]) {
+        if (!ALL_CATEGORY_ICONS[iconId]) {
             return DEFAULT_CATEGORY_ICON.icon;
         }
 
-        return ALL_CATEGORY_ICONS[iconId as string].icon;
+        return ALL_CATEGORY_ICONS[iconId].icon;
     }
 
     function getAccountIconStyle(color?: ColorValue | string, defaultColor?: ColorValue | string, additionalColorAttr?: string): Record<IconItemStyleName, IconItemStyleValue> {
diff --git a/src/components/desktop/ConfirmDialog.vue b/src/components/desktop/ConfirmDialog.vue
index 3b58fc28..63c3ae88 100644
--- a/src/components/desktop/ConfirmDialog.vue
+++ b/src/components/desktop/ConfirmDialog.vue
@@ -57,15 +57,15 @@ function open(titleOrText: string, textOrOptions?: string | Record<string, unkno
     } else if (isString(textOrOptions)) { // second parameter is text
         if (!options) {
             titleContent.value = tt(titleOrText);
-            textContent.value = tt(textOrOptions as string);
+            textContent.value = tt(textOrOptions);
         } else {
             titleContent.value = tt(titleOrText, options);
-            textContent.value = tt(textOrOptions as string, options);
+            textContent.value = tt(textOrOptions, options);
         }
     }
 
-    if (options && isString(options.color)) {
-        finalColor.value = (options.color as string) || 'primary';
+    if (options && isString(options['color'])) {
+        finalColor.value = (options['color'] as string) || 'primary';
     }
 
     return new Promise((resolve, reject) => {
diff --git a/src/components/desktop/SnackBar.vue b/src/components/desktop/SnackBar.vue
index 29bb00ad..e01a9f6a 100644
--- a/src/components/desktop/SnackBar.vue
+++ b/src/components/desktop/SnackBar.vue
@@ -13,7 +13,7 @@ import { ref, watch } from 'vue';
 
 import { useI18n } from '@/locales/helpers.ts';
 
-import { isObject } from '@/lib/common.ts';
+import { isObject, isString } from '@/lib/common.ts';
 
 const emit = defineEmits<{
     (e: 'update:show', value: boolean): void;
@@ -37,10 +37,10 @@ function showMessage(message: string, options?: Record<string, unknown>): void {
 function showError(error: string | { message: string }): void {
     showState.value = true;
 
-    if (isObject(error) && (error as { message: string }).message) {
-        messageContent.value = te((error as { message: string }).message);
-    } else {
-        messageContent.value = te(error as string);
+    if (isObject(error) && error.message) {
+        messageContent.value = te(error.message);
+    } else if (isString(error)) {
+        messageContent.value = te(error);
     }
 }
 
diff --git a/src/components/mobile/NumberPadSheet.vue b/src/components/mobile/NumberPadSheet.vue
index ed8094dc..cffb5e23 100644
--- a/src/components/mobile/NumberPadSheet.vue
+++ b/src/components/mobile/NumberPadSheet.vue
@@ -210,7 +210,7 @@ function inputNum(num: number): void {
     if (isNumber(props.minValue)) {
         const current = parseAmount(newValue);
 
-        if (current < (props.minValue as number)) {
+        if (current < (props.minValue)) {
             return;
         }
     }
@@ -218,7 +218,7 @@ function inputNum(num: number): void {
     if (isNumber(props.maxValue)) {
         const current = parseAmount(newValue);
 
-        if (current > (props.maxValue as number)) {
+        if (current > (props.maxValue)) {
             return;
         }
     }
@@ -308,14 +308,14 @@ function confirm(): boolean {
         }
 
         if (isNumber(props.minValue)) {
-            if (finalValue < (props.minValue as number)) {
+            if (finalValue < (props.minValue)) {
                 showToast('Numeric Overflow');
                 return false;
             }
         }
 
         if (isNumber(props.maxValue)) {
-            if (finalValue > (props.maxValue as number)) {
+            if (finalValue > (props.maxValue)) {
                 showToast('Numeric Overflow');
                 return false;
             }
diff --git a/src/lib/common.ts b/src/lib/common.ts
index f130909c..d74b9e1b 100644
--- a/src/lib/common.ts
+++ b/src/lib/common.ts
@@ -1,16 +1,17 @@
-export function isFunction(val: unknown): boolean {
+// eslint-disable-next-line @typescript-eslint/no-unsafe-function-type
+export function isFunction(val: unknown): val is Function {
     return typeof(val) === 'function';
 }
 
-export function isDefined(val: unknown): boolean {
-    return typeof val !== 'undefined';
+export function isDefined<T>(val: T | null | undefined): val is T {
+    return val !== null && typeof(val) !== 'undefined';
 }
 
-export function isObject(val: unknown): boolean {
+export function isObject(val: unknown): val is object {
     return val != null && typeof(val) === 'object' && !isArray(val);
 }
 
-export function isArray(val: unknown): boolean {
+export function isArray(val: unknown): val is [] {
     if (isFunction(Array.isArray)) {
         return Array.isArray(val);
     }
@@ -18,24 +19,24 @@ export function isArray(val: unknown): boolean {
     return Object.prototype.toString.call(val) === '[object Array]';
 }
 
-export function isString(val: unknown): boolean {
+export function isString(val: unknown): val is string {
     return typeof(val) === 'string';
 }
 
-export function isNumber(val: unknown): boolean {
+export function isNumber(val: unknown): val is number {
     return typeof(val) === 'number';
 }
 
-export function isInteger(val: unknown): boolean {
+export function isInteger(val: unknown): val is number {
     return Number.isInteger(val);
 }
 
-export function isBoolean(val: unknown): boolean {
+export function isBoolean(val: unknown): val is boolean {
     return typeof(val) === 'boolean';
 }
 
 export function isYearMonth(val: unknown): boolean {
-    if (typeof(val) !== 'string') {
+    if (!isString(val)) {
         return false;
     }
 
@@ -54,8 +55,8 @@ export function isEquals(obj1: unknown, obj2: unknown): boolean {
     }
 
     if (isArray(obj1) && isArray(obj2)) {
-        const arr1 = obj1 as unknown[];
-        const arr2 = obj2 as unknown[];
+        const arr1 = obj1;
+        const arr2 = obj2;
 
         if (arr1.length !== arr2.length) {
             return false;
@@ -69,8 +70,8 @@ export function isEquals(obj1: unknown, obj2: unknown): boolean {
 
         return true;
     } else if (isObject(obj1) && isObject(obj2)) {
-        const keys1 = Object.keys(obj1 as Record<string, unknown>);
-        const keys2 = Object.keys(obj2 as Record<string, unknown>);
+        const keys1 = Object.keys(obj1);
+        const keys2 = Object.keys(obj2);
 
         if (keys1.length !== keys2.length) {
             return false;
@@ -135,9 +136,9 @@ export function isObjectEmpty(obj: object): boolean {
 
 export function getNumberValue(value: unknown, defaultValue: number): number {
     if (isString(value)) {
-        return parseInt(value as string, 10);
+        return parseInt(value, 10);
     } else if (isNumber(value)) {
-        return value as number;
+        return value;
     } else {
         return defaultValue;
     }
@@ -254,7 +255,7 @@ export function stringToArrayBuffer(str: string): ArrayBuffer {
 }
 
 export function getFirstVisibleItem<T>(items: Record<string, T>[] | Record<string, Record<string, T>>, hiddenField: string): Record<string, T> | null {
-    if (isArray(items) && (items as Record<string, T>[]).length > 0) {
+    if (isArray(items) && items.length > 0) {
         const arr = items as Record<string, T>[];
 
         for (let i = 0; i < arr.length; i++) {
@@ -326,7 +327,7 @@ export function getNameByKeyValue<T>(src: Record<string, T>[] | Record<string, R
                 }
             }
         } else if (isNumber(value)) {
-            const index = value as number;
+            const index = value;
 
             if (arr[index]) {
                 const option = arr[index];
@@ -350,7 +351,7 @@ export function getNameByKeyValue<T>(src: Record<string, T>[] | Record<string, R
                 }
             }
         } else if (isString(value)) {
-            const key = value as string;
+            const key = value;
 
             if (obj[key]) {
                 const option = obj[key];
@@ -378,20 +379,20 @@ export function copyObjectTo(fromObject: Record<string, unknown> | undefined, to
         }
 
         const fromValue = fromObject[key];
-        const toValue = (toObject as Record<string, unknown>)[key];
+        const toValue = toObject[key];
 
         if (isArray(fromValue)) {
-            (toObject as Record<string, unknown>)[key] = copyArrayTo(fromValue as unknown[], toValue as unknown[]);
+            toObject[key] = copyArrayTo(fromValue, toValue as unknown[]);
         } else if (isObject(fromValue)) {
-            (toObject as Record<string, unknown>)[key] = copyObjectTo(fromValue as Record<string, unknown>, toValue as Record<string, unknown>);
+            toObject[key] = copyObjectTo(fromValue as Record<string, unknown>, toValue as Record<string, unknown>);
         } else {
             if (fromValue !== toValue) {
-                (toObject as Record<string, unknown>)[key] = fromValue;
+                toObject[key] = fromValue;
             }
         }
     }
 
-    return (toObject as Record<string, unknown>);
+    return toObject;
 }
 
 export function copyArrayTo<T>(fromArray: T[], toArray: T[]): T[] {
diff --git a/src/lib/currency.ts b/src/lib/currency.ts
index 9dbc21fc..6b808fac 100644
--- a/src/lib/currency.ts
+++ b/src/lib/currency.ts
@@ -14,7 +14,7 @@ export function getCurrencyFraction(currencyCode?: string): number | undefined {
 
 export function appendCurrencySymbol(value: unknown, currencyDisplayType: CurrencyDisplayType, currencyCode: string, currencyUnit: string, currencyName: string, isPlural: boolean): string | null {
     if (isNumber(value)) {
-        value = (value as number).toString();
+        value = value.toString();
     }
 
     if (!isString(value)) {
@@ -24,11 +24,11 @@ export function appendCurrencySymbol(value: unknown, currencyDisplayType: Curren
     const symbol = getAmountPrependAndAppendCurrencySymbol(currencyDisplayType, currencyCode, currencyUnit, currencyName, isPlural);
 
     if (!symbol) {
-        return value as string;
+        return value;
     }
 
     const separator = currencyDisplayType.separator || '';
-    let ret = value as string;
+    let ret = value;
 
     if (symbol.prependText) {
         ret = symbol.prependText + separator + ret;
diff --git a/src/lib/datetime.ts b/src/lib/datetime.ts
index c2fcac71..3a452384 100644
--- a/src/lib/datetime.ts
+++ b/src/lib/datetime.ts
@@ -185,7 +185,7 @@ export function parseDateFromUnixTime(unixTime: number, utcOffset?: number, curr
             currentUtcOffset = getTimezoneOffsetMinutes();
         }
 
-        unixTime = getDummyUnixTimeForLocalUsage(unixTime, utcOffset as number, currentUtcOffset as number);
+        unixTime = getDummyUnixTimeForLocalUsage(unixTime, utcOffset, currentUtcOffset);
     }
 
     return moment.unix(unixTime);
@@ -354,9 +354,9 @@ export function getYearMonthFirstUnixTime(yearMonth: YearMonth | string): number
     let yearMonthObj: YearMonth | null = null;
 
     if (isString(yearMonth)) {
-        yearMonthObj = getYearMonthObjectFromString(yearMonth as string);
-    } else if (isObject(yearMonth) && isYearMonthValid((yearMonth as YearMonth).year, (yearMonth as YearMonth).month)) {
-        yearMonthObj = yearMonth as YearMonth;
+        yearMonthObj = getYearMonthObjectFromString(yearMonth);
+    } else if (isObject(yearMonth) && isYearMonthValid(yearMonth.year, yearMonth.month)) {
+        yearMonthObj = yearMonth;
     }
 
     if (!yearMonthObj) {
@@ -375,15 +375,15 @@ export function getStartEndYearMonthRange(startYearMonth: YearMonth | string, en
     let endYearMonthObj: YearMonth | null = null;
 
     if (isString(startYearMonth)) {
-        startYearMonthObj = getYearMonthObjectFromString(startYearMonth as string);
+        startYearMonthObj = getYearMonthObjectFromString(startYearMonth);
     } else if (isObject(startYearMonth)) {
-        startYearMonthObj = startYearMonth as YearMonth;
+        startYearMonthObj = startYearMonth;
     }
 
     if (isString(endYearMonth)) {
-        endYearMonthObj = getYearMonthObjectFromString(endYearMonth as string);
+        endYearMonthObj = getYearMonthObjectFromString(endYearMonth);
     } else {
-        endYearMonthObj = endYearMonth as YearMonth;
+        endYearMonthObj = endYearMonth;
     }
 
     if (!startYearMonthObj || !endYearMonthObj) {
diff --git a/src/lib/numeral.ts b/src/lib/numeral.ts
index 6917b9ff..d60cdd44 100644
--- a/src/lib/numeral.ts
+++ b/src/lib/numeral.ts
@@ -9,7 +9,7 @@ export function appendDigitGroupingSymbol(value: number | string, options: Numbe
     if (isNumber(value)) {
         textualValue = value.toString();
     } else {
-        textualValue = value as string;
+        textualValue = value;
     }
 
     if (!textualValue) {
@@ -137,7 +137,7 @@ export function formatAmount(value: number | string, options: NumberFormatOption
     if (isNumber(value)) {
         textualValue = value.toString();
     } else {
-        textualValue = value as string;
+        textualValue = value;
     }
 
     if (!textualValue) {
@@ -157,7 +157,7 @@ export function formatAmount(value: number | string, options: NumberFormatOption
     const decimalSeparator = options.decimalSeparator || DecimalSeparator.Default.symbol;
     let decimalNumberCount = options.decimalNumberCount;
 
-    if (!isNumber(decimalNumberCount) || (decimalNumberCount as number) > MAX_SUPPORTED_DECIMAL_NUMBER_COUNT) {
+    if (!isNumber(decimalNumberCount) || decimalNumberCount > MAX_SUPPORTED_DECIMAL_NUMBER_COUNT) {
         decimalNumberCount = DEFAULT_DECIMAL_NUMBER_COUNT;
     }
 
diff --git a/src/locales/helpers.ts b/src/locales/helpers.ts
index 1614d4a3..e8596d44 100644
--- a/src/locales/helpers.ts
+++ b/src/locales/helpers.ts
@@ -488,7 +488,7 @@ export function useI18n() {
             return undefined;
         }
 
-        if (text && isTranslate) {
+        if (isTranslate) {
             return t(text);
         }
 
@@ -499,12 +499,12 @@ export function useI18n() {
         let finalMessage = '';
         let parameters = {};
 
-        if (isObject(message) && isObject((message as { error: ErrorResponse }).error)) {
-            const localizedError = getLocalizedError((message as { error: ErrorResponse }).error);
+        if (isObject(message) && isObject(message.error)) {
+            const localizedError = getLocalizedError(message.error);
             finalMessage = localizedError.message;
             parameters = getLocalizedErrorParameters(localizedError.parameters);
         } else if (isString(message)) {
-            finalMessage = message as string;
+            finalMessage = message;
         } else {
             return '';
         }
@@ -941,7 +941,7 @@ export function useI18n() {
             weekdayTypesMap[weekdayTypes[i]] = true;
         }
 
-        const allWeekDays = getAllWeekDays(firstDayOfWeek as number);
+        const allWeekDays = getAllWeekDays(firstDayOfWeek);
         const finalWeekdayNames = [];
 
         for (let i = 0; i < allWeekDays.length; i++) {
@@ -1094,7 +1094,7 @@ export function useI18n() {
             value = value.toString();
         }
 
-        let textualValue = value as string;
+        let textualValue = value;
         const isPlural: boolean = textualValue !== '100' && textualValue !== '-100';
 
         if (!notConvertValue) {
diff --git a/src/models/transaction_category.ts b/src/models/transaction_category.ts
index 111d8ce6..f12c33ad 100644
--- a/src/models/transaction_category.ts
+++ b/src/models/transaction_category.ts
@@ -37,7 +37,7 @@ export class TransactionCategory implements TransactionCategoryInfoResponse {
     }
 
     get subCategories(): TransactionCategoryInfoResponse[] | undefined {
-        if (typeof this.secondaryCategories === 'undefined') {
+        if (typeof(this.secondaryCategories) === 'undefined') {
             return undefined;
         }
 
diff --git a/src/stores/overview.ts b/src/stores/overview.ts
index 09934cff..81e00cd7 100644
--- a/src/stores/overview.ts
+++ b/src/stores/overview.ts
@@ -210,13 +210,13 @@ export const useOverviewStore = defineStore('overview', () => {
                         const expenseAmount = exchangeRatesStore.getExchangedAmount(amount.expenseAmount, amount.currency, defaultCurrency);
 
                         if (isNumber(incomeAmount)) {
-                            totalIncomeAmount += Math.floor(incomeAmount as number);
+                            totalIncomeAmount += Math.floor(incomeAmount);
                         } else {
                             hasUnCalculatedTotalIncome = true;
                         }
 
                         if (isNumber(expenseAmount)) {
-                            totalExpenseAmount += Math.floor(expenseAmount as number);
+                            totalExpenseAmount += Math.floor(expenseAmount);
                         } else {
                             hasUnCalculatedTotalExpense = true;
                         }