Candle Stick In Terminal

candle-sticks.ts

const UP_MOVE = 1;
const DOWN_MOVE = -1;
const SYMBOL_STICK = "│";
const SYMBOL_CANDLE = "┃";
const SYMBOL_HALF_TOP = "╽";
const SYMBOL_HALF_BOTTOM = "╿";
const SYMBOL_HALF_CANDLE_TOP = "╻";
const SYMBOL_HALF_CANDLE_BOTTOM = "╹";
const SYMBOL_HALF_STICK_TOP = "╷";
const SYMBOL_HALF_STICK_BOTTOM = "╵";
const SYMBOL_NOTHING = " ";

interface DataPoint {
    open : number,
    high : number,
    low : number,
    close : number
}

function draw( height : number, data : DataPoint[] ) {

    const [MAX, MIN] = data.reduce( ( [prevMax, prevMin], item ) => [
        Math.max( prevMax,
            item.open,
            item.high,
            item.low,
            item.close ),
        Math.min( prevMin,
            item.open,
            item.high,
            item.low,
            item.close )
    ], [0, 0] );

    console.log( data );
    console.log( "\n" );

    const cells = data.map( point => [
        Math.ceil( point.open / MAX * (height - 1) ),
        Math.ceil( point.high / MAX * (height - 1) ),
        Math.floor( point.low / MAX * (height - 1) ),
        Math.floor( point.close / MAX * (height - 1) ),
    ] );

    return new Array( height )
        .fill( "" )
        .map( ( _, index ) => index )
        .reverse()
        .map( row => [
            ...cells.map( ( [open, high, low, close], index ) => {
                // console.log( { index, row, open, high, low, close } );
                if ( Math.max( open, high ) < row || Math.min( low, close ) > row ) {
                    return " ";
                } else {

                    const start = Math.max( open, close );
                    const end = Math.min( open, close );

                    if ( row > start ) {
                        if ( high === row ) {
                            return SYMBOL_HALF_STICK_TOP;
                        } else {
                            return SYMBOL_STICK;
                        }
                    }

                    if ( row < end ) {
                        if ( low === row ) {
                            return SYMBOL_HALF_STICK_BOTTOM;
                        } else {
                            return SYMBOL_STICK;
                        }
                    }

                    if ( row === start ) {
                        if ( start < high ) {
                            return SYMBOL_HALF_TOP;
                        } else {
                            return SYMBOL_HALF_CANDLE_TOP;
                        }
                    }

                    if ( row === end ) {
                        if ( end > low ) {
                            return SYMBOL_HALF_BOTTOM;
                        } else {
                            return SYMBOL_HALF_CANDLE_BOTTOM;
                        }
                    }

                    if ( row < start && row > end ) {
                        return SYMBOL_CANDLE;
                    }

                    return "X";
                }
            } ),
            "\n"
        ] )
        .flat( 2 )
        .join( "" );

}

console.log( draw( 10, [
    { open : 1, high : 1, low : 0, close : 1 },
    { open : 1, high : 3, low : 0, close : 2 },
    { open : 4, high : 6, low : 2, close : 3 },
    { open : 1, high : 2, low : 1, close : 1 }
] ) );

/*
OUTPUT : 

 [
  { open: 1, high: 1, low: 0, close: 1 },
  { open: 1, high: 3, low: 0, close: 2 },
  { open: 4, high: 6, low: 2, close: 3 },
  { open: 1, high: 2, low: 1, close: 1 }
]


  ╷
  │
  │
  ╽
 ╷┃
 │╿
 ╽╵╷
╻╿ ╽
╿│ ╹
╵╵
*/

goal.txt

│
┷ ━
█ █
┯ █
│ █
  ┯
  │