Oibackoff typing generator (short and working!)

generator-v4.ts

import * as fs from 'fs';

// Settings
let generics = ['a','b','c','d','e','f','g','h','i','j','k'];
let paramGenerics = ['o','p','q','r','s','t','u','v','w','x','y','z'];
let parameterName = 'p';

// File
let fileStream = fs.createWriteStream('index.d.ts');

// Generate the instance
let lines: string[] = [];
let functionCallbackNotation = `callback: (${generics.map(v => `${v}: ${v.toUpperCase()}`).join(', ')}) => any`;

let callbackArr: string[] = [];
for (let genericNumber = 0; genericNumber < generics.length; genericNumber++) {
    let str = `${generics[genericNumber]}: ${generics[genericNumber].toUpperCase()}`;
    if (genericNumber === 2) {
        str = `priorErrorsOr${generics[genericNumber].toUpperCase()}: ${generics[genericNumber].toUpperCase()} | ${generics[0].toUpperCase()}[]`;
    }
    if (genericNumber == 1) {
        str += ' | null';
    }
    if (genericNumber > 0) {
        str += ' | undefined';
    }
    callbackArr.push(str);
}
let callbackNotation = `callback: (${callbackArr.join(', ')}) => void`;

// Loop through each allowed amount of backoff parameters
for (let maxParamNumber = 0; maxParamNumber <= paramGenerics.length; maxParamNumber++) {
    
    // Build the list of backoff parameters
    let backoffParams: string[] = [];
    let callbackParams: string[] = [];
    for (let paramNumber = 0; paramNumber < maxParamNumber; paramNumber++) {
        backoffParams.push(`${parameterName}${paramNumber}: ${paramGenerics[paramNumber].toUpperCase()}`)
        callbackParams.push(`${parameterName}${paramNumber}: ${paramGenerics[paramNumber].toUpperCase()}`)
    }
    callbackParams.push(functionCallbackNotation);

    let genericNotation = `<${generics.concat(paramGenerics.slice(0, maxParamNumber)).map(v => v.toUpperCase()).join(',')}>`;

    let immediateArgs: string[] = [];
    immediateArgs.push(`fn: (${callbackParams.join(', ')}) => any`)
    immediateArgs = immediateArgs.concat(backoffParams);
    immediateArgs.push('intermediate: BackoffIntermediate<A>');
    immediateArgs.push(callbackNotation);
    lines.push(`${genericNotation}(${immediateArgs.join(', ')}): void;`)

    let noImmediateArgs: string[] = [];
    noImmediateArgs.push(`fn: (${callbackParams.join(', ')}) => any`)
    noImmediateArgs = noImmediateArgs.concat(backoffParams);
    noImmediateArgs.push(callbackNotation);
    lines.push(`${genericNotation}(${noImmediateArgs.join(', ')}): void;`)

}
fileStream.write(`export declare interface BackoffInstance {\n    ${lines.join('\n    ')}\n}\n`);

index.d.ts

export declare interface BackoffInstance {
    <A,B,C,D,E,F,G,H,I,J,K>(fn: (callback: (a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J, k: K) => any) => any, intermediate: BackoffIntermediate<A>, callback: (a: A, b: B | null | undefined, priorErrorsOrC: C | A[] | undefined, d: D | undefined, e: E | undefined, f: F | undefined, g: G | undefined, h: H | undefined, i: I | undefined, j: J | undefined, k: K | undefined) => void): void;
    <A,B,C,D,E,F,G,H,I,J,K>(fn: (callback: (a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J, k: K) => any) => any, callback: (a: A, b: B | null | undefined, priorErrorsOrC: C | A[] | undefined, d: D | undefined, e: E | undefined, f: F | undefined, g: G | undefined, h: H | undefined, i: I | undefined, j: J | undefined, k: K | undefined) => void): void;
    <A,B,C,D,E,F,G,H,I,J,K,O>(fn: (p0: O, callback: (a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J, k: K) => any) => any, p0: O, intermediate: BackoffIntermediate<A>, callback: (a: A, b: B | null | undefined, priorErrorsOrC: C | A[] | undefined, d: D | undefined, e: E | undefined, f: F | undefined, g: G | undefined, h: H | undefined, i: I | undefined, j: J | undefined, k: K | undefined) => void): void;
    <A,B,C,D,E,F,G,H,I,J,K,O>(fn: (p0: O, callback: (a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J, k: K) => any) => any, p0: O, callback: (a: A, b: B | null | undefined, priorErrorsOrC: C | A[] | undefined, d: D | undefined, e: E | undefined, f: F | undefined, g: G | undefined, h: H | undefined, i: I | undefined, j: J | undefined, k: K | undefined) => void): void;
    <A,B,C,D,E,F,G,H,I,J,K,O,P>(fn: (p0: O, p1: P, callback: (a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J, k: K) => any) => any, p0: O, p1: P, intermediate: BackoffIntermediate<A>, callback: (a: A, b: B | null | undefined, priorErrorsOrC: C | A[] | undefined, d: D | undefined, e: E | undefined, f: F | undefined, g: G | undefined, h: H | undefined, i: I | undefined, j: J | undefined, k: K | undefined) => void): void;
    <A,B,C,D,E,F,G,H,I,J,K,O,P>(fn: (p0: O, p1: P, callback: (a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J, k: K) => any) => any, p0: O, p1: P, callback: (a: A, b: B | null | undefined, priorErrorsOrC: C | A[] | undefined, d: D | undefined, e: E | undefined, f: F | undefined, g: G | undefined, h: H | undefined, i: I | undefined, j: J | undefined, k: K | undefined) => void): void;
    <A,B,C,D,E,F,G,H,I,J,K,O,P,Q>(fn: (p0: O, p1: P, p2: Q, callback: (a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J, k: K) => any) => any, p0: O, p1: P, p2: Q, intermediate: BackoffIntermediate<A>, callback: (a: A, b: B | null | undefined, priorErrorsOrC: C | A[] | undefined, d: D | undefined, e: E | undefined, f: F | undefined, g: G | undefined, h: H | undefined, i: I | undefined, j: J | undefined, k: K | undefined) => void): void;
    <A,B,C,D,E,F,G,H,I,J,K,O,P,Q>(fn: (p0: O, p1: P, p2: Q, callback: (a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J, k: K) => any) => any, p0: O, p1: P, p2: Q, callback: (a: A, b: B | null | undefined, priorErrorsOrC: C | A[] | undefined, d: D | undefined, e: E | undefined, f: F | undefined, g: G | undefined, h: H | undefined, i: I | undefined, j: J | undefined, k: K | undefined) => void): void;
    <A,B,C,D,E,F,G,H,I,J,K,O,P,Q,R>(fn: (p0: O, p1: P, p2: Q, p3: R, callback: (a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J, k: K) => any) => any, p0: O, p1: P, p2: Q, p3: R, intermediate: BackoffIntermediate<A>, callback: (a: A, b: B | null | undefined, priorErrorsOrC: C | A[] | undefined, d: D | undefined, e: E | undefined, f: F | undefined, g: G | undefined, h: H | undefined, i: I | undefined, j: J | undefined, k: K | undefined) => void): void;
    <A,B,C,D,E,F,G,H,I,J,K,O,P,Q,R>(fn: (p0: O, p1: P, p2: Q, p3: R, callback: (a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J, k: K) => any) => any, p0: O, p1: P, p2: Q, p3: R, callback: (a: A, b: B | null | undefined, priorErrorsOrC: C | A[] | undefined, d: D | undefined, e: E | undefined, f: F | undefined, g: G | undefined, h: H | undefined, i: I | undefined, j: J | undefined, k: K | undefined) => void): void;
    <A,B,C,D,E,F,G,H,I,J,K,O,P,Q,R,S>(fn: (p0: O, p1: P, p2: Q, p3: R, p4: S, callback: (a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J, k: K) => any) => any, p0: O, p1: P, p2: Q, p3: R, p4: S, intermediate: BackoffIntermediate<A>, callback: (a: A, b: B | null | undefined, priorErrorsOrC: C | A[] | undefined, d: D | undefined, e: E | undefined, f: F | undefined, g: G | undefined, h: H | undefined, i: I | undefined, j: J | undefined, k: K | undefined) => void): void;
    <A,B,C,D,E,F,G,H,I,J,K,O,P,Q,R,S>(fn: (p0: O, p1: P, p2: Q, p3: R, p4: S, callback: (a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J, k: K) => any) => any, p0: O, p1: P, p2: Q, p3: R, p4: S, callback: (a: A, b: B | null | undefined, priorErrorsOrC: C | A[] | undefined, d: D | undefined, e: E | undefined, f: F | undefined, g: G | undefined, h: H | undefined, i: I | undefined, j: J | undefined, k: K | undefined) => void): void;
    <A,B,C,D,E,F,G,H,I,J,K,O,P,Q,R,S,T>(fn: (p0: O, p1: P, p2: Q, p3: R, p4: S, p5: T, callback: (a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J, k: K) => any) => any, p0: O, p1: P, p2: Q, p3: R, p4: S, p5: T, intermediate: BackoffIntermediate<A>, callback: (a: A, b: B | null | undefined, priorErrorsOrC: C | A[] | undefined, d: D | undefined, e: E | undefined, f: F | undefined, g: G | undefined, h: H | undefined, i: I | undefined, j: J | undefined, k: K | undefined) => void): void;
    <A,B,C,D,E,F,G,H,I,J,K,O,P,Q,R,S,T>(fn: (p0: O, p1: P, p2: Q, p3: R, p4: S, p5: T, callback: (a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J, k: K) => any) => any, p0: O, p1: P, p2: Q, p3: R, p4: S, p5: T, callback: (a: A, b: B | null | undefined, priorErrorsOrC: C | A[] | undefined, d: D | undefined, e: E | undefined, f: F | undefined, g: G | undefined, h: H | undefined, i: I | undefined, j: J | undefined, k: K | undefined) => void): void;
    <A,B,C,D,E,F,G,H,I,J,K,O,P,Q,R,S,T,U>(fn: (p0: O, p1: P, p2: Q, p3: R, p4: S, p5: T, p6: U, callback: (a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J, k: K) => any) => any, p0: O, p1: P, p2: Q, p3: R, p4: S, p5: T, p6: U, intermediate: BackoffIntermediate<A>, callback: (a: A, b: B | null | undefined, priorErrorsOrC: C | A[] | undefined, d: D | undefined, e: E | undefined, f: F | undefined, g: G | undefined, h: H | undefined, i: I | undefined, j: J | undefined, k: K | undefined) => void): void;
    <A,B,C,D,E,F,G,H,I,J,K,O,P,Q,R,S,T,U>(fn: (p0: O, p1: P, p2: Q, p3: R, p4: S, p5: T, p6: U, callback: (a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J, k: K) => any) => any, p0: O, p1: P, p2: Q, p3: R, p4: S, p5: T, p6: U, callback: (a: A, b: B | null | undefined, priorErrorsOrC: C | A[] | undefined, d: D | undefined, e: E | undefined, f: F | undefined, g: G | undefined, h: H | undefined, i: I | undefined, j: J | undefined, k: K | undefined) => void): void;
    <A,B,C,D,E,F,G,H,I,J,K,O,P,Q,R,S,T,U,V>(fn: (p0: O, p1: P, p2: Q, p3: R, p4: S, p5: T, p6: U, p7: V, callback: (a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J, k: K) => any) => any, p0: O, p1: P, p2: Q, p3: R, p4: S, p5: T, p6: U, p7: V, intermediate: BackoffIntermediate<A>, callback: (a: A, b: B | null | undefined, priorErrorsOrC: C | A[] | undefined, d: D | undefined, e: E | undefined, f: F | undefined, g: G | undefined, h: H | undefined, i: I | undefined, j: J | undefined, k: K | undefined) => void): void;
    <A,B,C,D,E,F,G,H,I,J,K,O,P,Q,R,S,T,U,V>(fn: (p0: O, p1: P, p2: Q, p3: R, p4: S, p5: T, p6: U, p7: V, callback: (a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J, k: K) => any) => any, p0: O, p1: P, p2: Q, p3: R, p4: S, p5: T, p6: U, p7: V, callback: (a: A, b: B | null | undefined, priorErrorsOrC: C | A[] | undefined, d: D | undefined, e: E | undefined, f: F | undefined, g: G | undefined, h: H | undefined, i: I | undefined, j: J | undefined, k: K | undefined) => void): void;
    <A,B,C,D,E,F,G,H,I,J,K,O,P,Q,R,S,T,U,V,W>(fn: (p0: O, p1: P, p2: Q, p3: R, p4: S, p5: T, p6: U, p7: V, p8: W, callback: (a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J, k: K) => any) => any, p0: O, p1: P, p2: Q, p3: R, p4: S, p5: T, p6: U, p7: V, p8: W, intermediate: BackoffIntermediate<A>, callback: (a: A, b: B | null | undefined, priorErrorsOrC: C | A[] | undefined, d: D | undefined, e: E | undefined, f: F | undefined, g: G | undefined, h: H | undefined, i: I | undefined, j: J | undefined, k: K | undefined) => void): void;
    <A,B,C,D,E,F,G,H,I,J,K,O,P,Q,R,S,T,U,V,W>(fn: (p0: O, p1: P, p2: Q, p3: R, p4: S, p5: T, p6: U, p7: V, p8: W, callback: (a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J, k: K) => any) => any, p0: O, p1: P, p2: Q, p3: R, p4: S, p5: T, p6: U, p7: V, p8: W, callback: (a: A, b: B | null | undefined, priorErrorsOrC: C | A[] | undefined, d: D | undefined, e: E | undefined, f: F | undefined, g: G | undefined, h: H | undefined, i: I | undefined, j: J | undefined, k: K | undefined) => void): void;
    <A,B,C,D,E,F,G,H,I,J,K,O,P,Q,R,S,T,U,V,W,X>(fn: (p0: O, p1: P, p2: Q, p3: R, p4: S, p5: T, p6: U, p7: V, p8: W, p9: X, callback: (a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J, k: K) => any) => any, p0: O, p1: P, p2: Q, p3: R, p4: S, p5: T, p6: U, p7: V, p8: W, p9: X, intermediate: BackoffIntermediate<A>, callback: (a: A, b: B | null | undefined, priorErrorsOrC: C | A[] | undefined, d: D | undefined, e: E | undefined, f: F | undefined, g: G | undefined, h: H | undefined, i: I | undefined, j: J | undefined, k: K | undefined) => void): void;
    <A,B,C,D,E,F,G,H,I,J,K,O,P,Q,R,S,T,U,V,W,X>(fn: (p0: O, p1: P, p2: Q, p3: R, p4: S, p5: T, p6: U, p7: V, p8: W, p9: X, callback: (a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J, k: K) => any) => any, p0: O, p1: P, p2: Q, p3: R, p4: S, p5: T, p6: U, p7: V, p8: W, p9: X, callback: (a: A, b: B | null | undefined, priorErrorsOrC: C | A[] | undefined, d: D | undefined, e: E | undefined, f: F | undefined, g: G | undefined, h: H | undefined, i: I | undefined, j: J | undefined, k: K | undefined) => void): void;
    <A,B,C,D,E,F,G,H,I,J,K,O,P,Q,R,S,T,U,V,W,X,Y>(fn: (p0: O, p1: P, p2: Q, p3: R, p4: S, p5: T, p6: U, p7: V, p8: W, p9: X, p10: Y, callback: (a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J, k: K) => any) => any, p0: O, p1: P, p2: Q, p3: R, p4: S, p5: T, p6: U, p7: V, p8: W, p9: X, p10: Y, intermediate: BackoffIntermediate<A>, callback: (a: A, b: B | null | undefined, priorErrorsOrC: C | A[] | undefined, d: D | undefined, e: E | undefined, f: F | undefined, g: G | undefined, h: H | undefined, i: I | undefined, j: J | undefined, k: K | undefined) => void): void;
    <A,B,C,D,E,F,G,H,I,J,K,O,P,Q,R,S,T,U,V,W,X,Y>(fn: (p0: O, p1: P, p2: Q, p3: R, p4: S, p5: T, p6: U, p7: V, p8: W, p9: X, p10: Y, callback: (a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J, k: K) => any) => any, p0: O, p1: P, p2: Q, p3: R, p4: S, p5: T, p6: U, p7: V, p8: W, p9: X, p10: Y, callback: (a: A, b: B | null | undefined, priorErrorsOrC: C | A[] | undefined, d: D | undefined, e: E | undefined, f: F | undefined, g: G | undefined, h: H | undefined, i: I | undefined, j: J | undefined, k: K | undefined) => void): void;
    <A,B,C,D,E,F,G,H,I,J,K,O,P,Q,R,S,T,U,V,W,X,Y,Z>(fn: (p0: O, p1: P, p2: Q, p3: R, p4: S, p5: T, p6: U, p7: V, p8: W, p9: X, p10: Y, p11: Z, callback: (a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J, k: K) => any) => any, p0: O, p1: P, p2: Q, p3: R, p4: S, p5: T, p6: U, p7: V, p8: W, p9: X, p10: Y, p11: Z, intermediate: BackoffIntermediate<A>, callback: (a: A, b: B | null | undefined, priorErrorsOrC: C | A[] | undefined, d: D | undefined, e: E | undefined, f: F | undefined, g: G | undefined, h: H | undefined, i: I | undefined, j: J | undefined, k: K | undefined) => void): void;
    <A,B,C,D,E,F,G,H,I,J,K,O,P,Q,R,S,T,U,V,W,X,Y,Z>(fn: (p0: O, p1: P, p2: Q, p3: R, p4: S, p5: T, p6: U, p7: V, p8: W, p9: X, p10: Y, p11: Z, callback: (a: A, b: B, c: C, d: D, e: E, f: F, g: G, h: H, i: I, j: J, k: K) => any) => any, p0: O, p1: P, p2: Q, p3: R, p4: S, p5: T, p6: U, p7: V, p8: W, p9: X, p10: Y, p11: Z, callback: (a: A, b: B | null | undefined, priorErrorsOrC: C | A[] | undefined, d: D | undefined, e: E | undefined, f: F | undefined, g: G | undefined, h: H | undefined, i: I | undefined, j: J | undefined, k: K | undefined) => void): void;
}