diff --git a/package.json b/package.json
index dd12376..63ec61c 100755
--- a/package.json
+++ b/package.json
@@ -27,10 +27,10 @@
     "check-types": "tsc --noEmit",
     "clean": "rimraf lib lib-esm",
     "eslint": "eslint src --cache",
-    "eslint:fix": "npm run eslint -- --fix",
+    "eslint-fix": "npm run eslint -- --fix",
     "prepack": "npm run tsc",
     "prettier": "prettier --check src",
-    "prettier:fix": "prettier --write src",
+    "prettier-write": "prettier --write src",
     "test": "npm run test-only && npm run eslint && npm run prettier && npm run check-types",
     "test-only": "jest --coverage",
     "tsc": "npm run clean && npm run tsc-cjs && npm run tsc-esm",
@@ -38,18 +38,16 @@
     "tsc-esm": "tsc --project tsconfig.esm.json"
   },
   "devDependencies": {
-    "@types/jest": "^29.2.3",
-    "cheminfo-build": "^1.1.11",
-    "cheminfo-types": "^1.4.0",
-    "eslint": "^8.25.0",
-    "eslint-config-cheminfo-typescript": "^11.2.2",
-    "eslint-plugin-import": "^2.28.0",
-    "jest": "^29.3.1",
-    "prettier": "^2.7.1",
-    "ts-jest": "^29.0.3",
-    "typescript": "^4.9.3"
+    "@types/jest": "^29.5.3",
+    "cheminfo-types": "^1.7.2",
+    "eslint": "^8.46.0",
+    "eslint-config-cheminfo-typescript": "^12.0.4",
+    "jest": "^29.6.2",
+    "prettier": "^3.0.1",
+    "ts-jest": "^29.1.1",
+    "typescript": "^5.1.6"
   },
   "dependencies": {
-    "iobuffer": "^5.2.1"
+    "iobuffer": "^5.3.2"
   }
 }
diff --git a/src/__tests__/attributeExists.test.ts b/src/__tests__/attributeExists.test.ts
index 78ed5f7..1084cfa 100755
--- a/src/__tests__/attributeExists.test.ts
+++ b/src/__tests__/attributeExists.test.ts
@@ -7,7 +7,7 @@ const pathFiles = `${__dirname}/files/`;
 test('attributeExists', () => {
   const data = readFileSync(`${pathFiles}P071.CDF`);
 
-  let reader = new NetCDFReader(data);
+  const reader = new NetCDFReader(data);
   expect(reader.attributeExists('operator_name')).toBe(true);
   expect(reader.attributeExists('operator_nameXX')).toBe(false);
 });
diff --git a/src/__tests__/dataVariableExists.test.ts b/src/__tests__/dataVariableExists.test.ts
index 7ccac0d..985e5d1 100755
--- a/src/__tests__/dataVariableExists.test.ts
+++ b/src/__tests__/dataVariableExists.test.ts
@@ -7,7 +7,7 @@ const pathFiles = `${__dirname}/files/`;
 test('dataVariableExists', () => {
   const data = readFileSync(`${pathFiles}P071.CDF`);
 
-  let reader = new NetCDFReader(data);
+  const reader = new NetCDFReader(data);
   expect(reader.dataVariableExists('instrument_name')).toBe(true);
   expect(reader.dataVariableExists('instrument_nameXX')).toBe(false);
 });
diff --git a/src/__tests__/getAttribute.test.ts b/src/__tests__/getAttribute.test.ts
index a690da9..751a6ea 100755
--- a/src/__tests__/getAttribute.test.ts
+++ b/src/__tests__/getAttribute.test.ts
@@ -7,6 +7,6 @@ const pathFiles = `${__dirname}/files/`;
 test('getAttribute', () => {
   const data = readFileSync(`${pathFiles}P071.CDF`);
 
-  let reader = new NetCDFReader(data);
+  const reader = new NetCDFReader(data);
   expect(reader.getAttribute('operator_name')).toBe('SC');
 });
diff --git a/src/__tests__/getDataVariableAsString.test.ts b/src/__tests__/getDataVariableAsString.test.ts
index b37067f..0cf7520 100755
--- a/src/__tests__/getDataVariableAsString.test.ts
+++ b/src/__tests__/getDataVariableAsString.test.ts
@@ -7,7 +7,7 @@ const pathFiles = `${__dirname}/files/`;
 test('getDataVariableAsString', () => {
   const data = readFileSync(`${pathFiles}P071.CDF`);
 
-  let reader = new NetCDFReader(data);
+  const reader = new NetCDFReader(data);
   expect(reader.getDataVariableAsString('instrument_name')).toBe(
     'Gas Chromatograph',
   );
diff --git a/src/__tests__/index.test.ts b/src/__tests__/index.test.ts
index 86bf0b0..9199f4e 100755
--- a/src/__tests__/index.test.ts
+++ b/src/__tests__/index.test.ts
@@ -17,7 +17,7 @@ describe('Read file', () => {
     // http://www.unidata.ucar.edu/software/netcdf/examples/madis-sao.cdl
     const data = readFileSync(`${pathFiles}madis-sao.nc`);
 
-    let reader = new NetCDFReader(data);
+    const reader = new NetCDFReader(data);
     expect(reader.version).toBe('classic format');
     expect(reader.recordDimension).toStrictEqual({
       length: 178,
@@ -94,14 +94,14 @@ describe('Read file', () => {
 
   it('read non-record variable', () => {
     const data = readFileSync(`${pathFiles}madis-sao.nc`);
-    let reader = new NetCDFReader(data);
+    const reader = new NetCDFReader(data);
 
     expect(reader.getDataVariable('nStaticIds')[0]).toBe(145);
   });
 
   it('read 2 dimensional variable', () => {
     const data = readFileSync(`${pathFiles}ichthyop.nc`);
-    let reader = new NetCDFReader(data);
+    const reader = new NetCDFReader(data);
     expect(reader.getDataVariable('time')).toHaveLength(49);
     expect(reader.getDataVariable('time')[0]).toBe(1547070300);
     expect(reader.getDataVariable('lat')).toHaveLength(49);
@@ -112,9 +112,9 @@ describe('Read file', () => {
 
   it('read record variable with string', () => {
     const data = readFileSync(`${pathFiles}madis-sao.nc`);
-    let reader = new NetCDFReader(data);
+    const reader = new NetCDFReader(data);
 
-    let record = reader.getDataVariable('wmoId');
+    const record = reader.getDataVariable('wmoId');
     expect(record[0]).toBe(71419);
     expect(record[1]).toBe(71415);
     expect(record[2]).toBe(71408);
@@ -122,11 +122,11 @@ describe('Read file', () => {
 
   it('read non-record variable with object', () => {
     const data = readFileSync(`${pathFiles}madis-sao.nc`);
-    let reader = new NetCDFReader(data);
-    let variables = reader.variables;
+    const reader = new NetCDFReader(data);
+    const variables = reader.variables;
 
-    let withString = reader.getDataVariable('staticIds');
-    let withObject = reader.getDataVariable(variables[1]);
+    const withString = reader.getDataVariable('staticIds');
+    const withObject = reader.getDataVariable(variables[1]);
     expect(withString[0]).toBe('W');
     expect(withString[1]).toBe('A');
     expect(withString[2]).toBe('F');
@@ -137,7 +137,7 @@ describe('Read file', () => {
 
   it('read non-existent variable string', () => {
     const data = readFileSync(`${pathFiles}madis-sao.nc`);
-    let reader = new NetCDFReader(data);
+    const reader = new NetCDFReader(data);
 
     expect(reader.getDataVariable.bind(reader, "n'importe quoi")).toThrow(
       'Not a valid NetCDF v3.x file: variable not found',
@@ -146,7 +146,7 @@ describe('Read file', () => {
 
   it('read 64 bit offset file', () => {
     const data = readFileSync(`${pathFiles}model1_md2.nc`);
-    let reader = new NetCDFReader(data);
+    const reader = new NetCDFReader(data);
     expect(reader.version).toBe('64-bit offset format');
     expect(reader.getDataVariable('cell_angular')[0]).toBe('a');
     expect(reader.getDataVariable('cell_spatial')[0]).toBe('a');
@@ -154,13 +154,13 @@ describe('Read file', () => {
 
   it('read agilent hplc file file', () => {
     const data = readFileSync(`${pathFiles}agilent_hplc.cdf`);
-    let reader = new NetCDFReader(data);
+    const reader = new NetCDFReader(data);
 
     expect(reader.version).toBe('classic format');
 
-    let variables = [];
+    const variables = [];
 
-    for (let variable of reader.variables) {
+    for (const variable of reader.variables) {
       const value = reader.getDataVariable(variable);
       variables.push({ value, ...variable });
     }
diff --git a/src/__tests__/toString.test.ts b/src/__tests__/toString.test.ts
index 96ffc46..aa2f99a 100755
--- a/src/__tests__/toString.test.ts
+++ b/src/__tests__/toString.test.ts
@@ -7,6 +7,6 @@ const pathFiles = `${__dirname}/files/`;
 test('toString', () => {
   const data = readFileSync(`${pathFiles}P071.CDF`);
 
-  let reader = new NetCDFReader(data);
+  const reader = new NetCDFReader(data);
   expect(reader.toString()).toMatchSnapshot();
 });
diff --git a/src/data.ts b/src/data.ts
index e394164..37bd206 100644
--- a/src/data.ts
+++ b/src/data.ts
@@ -13,7 +13,7 @@ import { num2bytes, str2num, readType } from './types';
 export function nonRecord(
   buffer: IOBuffer,
   variable: Header['variables'][number],
-): ReturnType<typeof readType>[] {
+): Array<ReturnType<typeof readType>> {
   // variable type
   const type = str2num(variable.type);
 
@@ -21,7 +21,7 @@ export function nonRecord(
   const size = variable.size / num2bytes(type);
 
   // iterates over the data
-  let data = new Array(size);
+  const data = new Array(size);
   for (let i = 0; i < size; i++) {
     data[i] = readType(buffer, type, 1);
   }
@@ -40,7 +40,7 @@ export function record(
   buffer: IOBuffer,
   variable: Header['variables'][number],
   recordDimension: Header['recordDimension'],
-): ReturnType<typeof readType>[] {
+): Array<ReturnType<typeof readType>> {
   // variable type
   const type = str2num(variable.type);
   const width = variable.size ? variable.size / num2bytes(type) : 1;
@@ -50,11 +50,11 @@ export function record(
   const size = recordDimension.length;
 
   // iterates over the data
-  let data = new Array(size);
+  const data = new Array(size);
   const step = recordDimension.recordStep;
   if (step) {
     for (let i = 0; i < size; i++) {
-      let currentOffset = buffer.offset;
+      const currentOffset = buffer.offset;
       data[i] = readType(buffer, type, width);
       buffer.seek(currentOffset + step);
     }
diff --git a/src/header.ts b/src/header.ts
index 0687939..ce1297a 100644
--- a/src/header.ts
+++ b/src/header.ts
@@ -66,12 +66,12 @@ export function header(buffer: IOBuffer, version: number): Header {
 
 export interface Dimensions {
   /* that is an array of dimension object:*/
-  dimensions: {
+  dimensions: Array<{
     /* name of the dimension*/
     name: string;
     /* size of the dimension */
     size: number;
-  }[];
+  }>;
   /*  id of the dimension that has unlimited size or undefined,*/
   recordId?: number;
   /* name of the dimension that has unlimited size */
@@ -203,7 +203,10 @@ export interface Variable {
   /* True if is a record variable, false otherwise (unlimited size) */
   record: boolean;
 }
-type Variables = { variables: Variable[]; recordStep: number };
+interface Variables {
+  variables: Variable[];
+  recordStep: number;
+}
 /**
  * @param buffer - Buffer for the file data
  * @param recordId - Id of the unlimited dimension (also called record dimension)
@@ -233,22 +236,22 @@ function variablesList(
     variables = new Array(variableSize);
     for (let v = 0; v < variableSize; v++) {
       // Read name
-      let name = readName(buffer);
+      const name = readName(buffer);
 
       // Read dimensionality of the variable
       const dimensionality = buffer.readUint32();
 
       // Index into the list of dimensions
-      let dimensionsIds = new Array(dimensionality);
+      const dimensionsIds = new Array(dimensionality);
       for (let dim = 0; dim < dimensionality; dim++) {
         dimensionsIds[dim] = buffer.readUint32();
       }
 
       // Read variables size
-      let attributes = attributesList(buffer);
+      const attributes = attributesList(buffer);
 
       // Read type
-      let type = buffer.readUint32();
+      const type = buffer.readUint32();
       notNetcdf(type < 1 && type > 6, `non valid type ${type}`);
 
       // Read variable size
diff --git a/src/toString.ts b/src/toString.ts
index 6e72946..ecb5569 100644
--- a/src/toString.ts
+++ b/src/toString.ts
@@ -1,22 +1,22 @@
 import { NetCDFReader } from './parser';
 
 export function toString(this: NetCDFReader) {
-  let result = [];
+  const result = [];
   result.push('DIMENSIONS');
-  for (let dimension of this.dimensions) {
+  for (const dimension of this.dimensions) {
     result.push(`  ${dimension.name.padEnd(30)} = size: ${dimension.size}`);
   }
 
   result.push('');
   result.push('GLOBAL ATTRIBUTES');
-  for (let attribute of this.globalAttributes) {
+  for (const attribute of this.globalAttributes) {
     result.push(`  ${attribute.name.padEnd(30)} = ${attribute.value}`);
   }
 
-  let variables = JSON.parse(JSON.stringify(this.variables));
+  const variables = JSON.parse(JSON.stringify(this.variables));
   result.push('');
   result.push('VARIABLES:');
-  for (let variable of variables) {
+  for (const variable of variables) {
     variable.value = this.getDataVariable(variable);
     let stringify = JSON.stringify(variable.value);
     if (stringify.length > 50) stringify = stringify.substring(0, 50);
diff --git a/src/types.ts b/src/types.ts
index 5833dd1..e490c62 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -93,7 +93,7 @@ function readNumber(
   bufferReader: () => number,
 ): number | number[] {
   if (size !== 1) {
-    let numbers = new Array(size);
+    const numbers = new Array(size);
     for (let i = 0; i < size; i++) {
       numbers[i] = bufferReader();
     }