How to use the mathjs.eval function in mathjs

if (analysis.xdataset) {
    if (
      analysis.stream.length === 0 || analysis.stream.split("/").length != 3
    ) {
      yield put({
        type: "ANALYSIS_ERROR",
        value: "Invalid correlation stream name"
      });
      return;
    }
    query.stream = analysis.stream;
    query.transform = analysis.transform;
  } else {
    // Make sure that dt is a number
    try {
      let dt = math.eval(analysis.dt);
      if (isNaN(dt) || dt < 0.001) {
        yield put({
          type: "ANALYSIS_ERROR",
          value: "Invalid time delta (" + analysis.dt + ")"
        });
        return;
      }
      query.dt = dt;
    } catch (e) {
      yield put({
        type: "ANALYSIS_ERROR",
        value: "Invalid time delta (" + analysis.dt + ")"
      });
      return;
    }
  }

const math = require('mathjs'); 

math.round(math.e, 3)            // 2.718
math.atan2(3, -3) / math.pi      // 0.75
math.log(10000, 10)              // 4
math.sqrt(-4)                    // 2i
math.derivative('x^2 + x', 'x')  // 2*x+1
math.pow([[-1, 2], [3, 1]], 2)
     // [[7, 0], [0, 7]]

// expressions
math.eval('1.2 * (2 + 4.5)')     // 7.8
math.eval('12.7 cm to inch')     // 5 inch
math.eval('sin(45 deg) ^ 2')     // 0.5
math.eval('9 / 3 + 2i')          // 3 + 2i
math.eval('det([-1, 2; 3, 1])')  // -7

// chaining
const res = math.chain(3)
    .add(4)
    .multiply(2)
    .done() // 14

toCrystal({result: res});

const msgReply = s => {
  let a1, a2, ans, b1, b2, eqn
  try {
    ans = '= ' + mathjs['eval'](s).toString()
  } catch (e) {
    a1 = Math.floor(Math.random() * 10)
    b1 = Math.floor(Math.random() * 10)
    a2 = Math.floor(Math.random() * 10)
    b2 = Math.floor(Math.random() * 10)
    eqn = '(' + a1 + ' + ' + b1 + 'i) * (' + a2 + ' + ' + b2 + 'i)'
    ans =
      "Sorry, I can't do that math. Did you know " + eqn + ' = ' + mathjs['eval'](eqn).toString() + '? True.'
  }
  return ans
}

private static signalAnimationHelper(channelAnimation: IChannelAnimation, value: number): IChannelInfo {
        const scope = {
            signal: value
        };
        return {
            downDecrement: channelAnimation.downDecrement === undefined ? undefined : math.eval(channelAnimation.downDecrement, scope),
            downDecrementDelay: channelAnimation.downDecrementDelay === undefined ? undefined : math.eval(channelAnimation.downDecrementDelay, scope),
            downHoldDelay: channelAnimation.downHoldDelay === undefined ? undefined : math.eval(channelAnimation.downHoldDelay, scope),
            downHoldLevel: channelAnimation.downHoldLevel === undefined ? undefined : math.eval(channelAnimation.downHoldLevel, scope),
            downMinimumLevel: channelAnimation.downMinimumLevel === undefined ? undefined : math.eval(channelAnimation.downMinimumLevel, scope),

            direction: channelAnimation.direction === undefined ? undefined : channelAnimation.direction,
            effectId: channelAnimation.effectId === undefined ? undefined : math.eval(channelAnimation.effectId, scope),

            upHoldDelay: channelAnimation.upHoldDelay === undefined ? undefined : math.eval(channelAnimation.upHoldDelay, scope),
            upHoldLevel: channelAnimation.upHoldLevel === undefined ? undefined : math.eval(channelAnimation.upHoldLevel, scope),
            upIncrement: channelAnimation.upIncrement === undefined ? undefined : math.eval(channelAnimation.upIncrement, scope),
            upIncrementDelay: channelAnimation.upIncrementDelay === undefined ? undefined : math.eval(channelAnimation.upIncrementDelay, scope),
            upMaximumLevel: channelAnimation.upMaximumLevel === undefined ? undefined : math.eval(channelAnimation.upMaximumLevel, scope),

            startDelay: channelAnimation.startDelay === undefined ? undefined : math.eval(channelAnimation.startDelay, scope),
            transition: channelAnimation.transition === undefined ? undefined : math.eval(channelAnimation.transition, scope),
        };

private signalAnimationHelper(channelAnimation: ChannelAnimation, value: number): ChannelInfo {
        const scope = {
            signal: value
        };
        return {
            upHoldLevel: channelAnimation.upHoldLevel === undefined ? undefined : math.eval(channelAnimation.upHoldLevel, scope),
            downHoldLevel: channelAnimation.downHoldLevel === undefined ? undefined : math.eval(channelAnimation.downHoldLevel, scope),
            upMaximumLevel: channelAnimation.upMaximumLevel === undefined ? undefined : math.eval(channelAnimation.upMaximumLevel, scope),
            downMinimumLevel: channelAnimation.downMinimumLevel === undefined ? undefined : math.eval(channelAnimation.downMinimumLevel, scope),
            upHoldDelay: channelAnimation.upHoldDelay === undefined ? undefined : math.eval(channelAnimation.upHoldDelay, scope),
            downHoldDelay: channelAnimation.downHoldDelay === undefined ? undefined : math.eval(channelAnimation.downHoldDelay, scope),
            upIncrement: channelAnimation.upIncrement === undefined ? undefined : math.eval(channelAnimation.upIncrement, scope),
            downDecrement: channelAnimation.downDecrement === undefined ? undefined : math.eval(channelAnimation.downDecrement, scope),
            upIncrementDelay: channelAnimation.upIncrementDelay === undefined ? undefined : math.eval(channelAnimation.upIncrementDelay, scope),
            downDecrementDelay: channelAnimation.downDecrementDelay === undefined ? undefined : math.eval(channelAnimation.downDecrementDelay, scope),
            startDelay: channelAnimation.startDelay === undefined ? undefined : math.eval(channelAnimation.startDelay, scope),
            effectId: channelAnimation.effectId === undefined ? undefined : math.eval(channelAnimation.effectId, scope),
            direction: channelAnimation.direction === undefined ? undefined : math.eval(channelAnimation.direction, scope),
            transition: channelAnimation.transition === undefined ? undefined : math.eval(channelAnimation.transition, scope),
        };
    }

_calculate(){
    let shorten = (str) => { return str.substring(1, str.length); };
    let shortened = shorten(this.state);
    let replaced = replaceReadableIdsWithMeans(shortened, this._inputs());
    let correct = math.eval(replaced);
    return {mean: correct, stdev: 0};
  }
  _inputs(){

export function computeCost(X, y, theta) {
  let m = y.length;

  let predictions = math.eval('X * theta', {
    X,
    theta,
  });

  let sqrErrors = math.eval('(predictions - y).^2', {
    predictions,
    y,
  });

  let J = math.eval(`1 / (2 * m) * sum(sqrErrors)`, {
    m,
    sqrErrors,
  });

  return J;
}

async function trigger(query) {
  if(!isNaN(query)) {
    return false;
  }
  try {
    mathjs.eval(query);
    return true;
  }
  catch (error) {
    return false;
  }
}

private signalAnimationHelper(channelAnimation: ChannelAnimation, value: number): ChannelInfo {
        const scope = {
            signal: value
        };
        return {
            upHoldLevel: channelAnimation.upHoldLevel === undefined ? undefined : math.eval(channelAnimation.upHoldLevel, scope),
            downHoldLevel: channelAnimation.downHoldLevel === undefined ? undefined : math.eval(channelAnimation.downHoldLevel, scope),
            upMaximumLevel: channelAnimation.upMaximumLevel === undefined ? undefined : math.eval(channelAnimation.upMaximumLevel, scope),
            downMinimumLevel: channelAnimation.downMinimumLevel === undefined ? undefined : math.eval(channelAnimation.downMinimumLevel, scope),
            upHoldDelay: channelAnimation.upHoldDelay === undefined ? undefined : math.eval(channelAnimation.upHoldDelay, scope),
            downHoldDelay: channelAnimation.downHoldDelay === undefined ? undefined : math.eval(channelAnimation.downHoldDelay, scope),
            upIncrement: channelAnimation.upIncrement === undefined ? undefined : math.eval(channelAnimation.upIncrement, scope),
            downDecrement: channelAnimation.downDecrement === undefined ? undefined : math.eval(channelAnimation.downDecrement, scope),
            upIncrementDelay: channelAnimation.upIncrementDelay === undefined ? undefined : math.eval(channelAnimation.upIncrementDelay, scope),
            downDecrementDelay: channelAnimation.downDecrementDelay === undefined ? undefined : math.eval(channelAnimation.downDecrementDelay, scope),
            startDelay: channelAnimation.startDelay === undefined ? undefined : math.eval(channelAnimation.startDelay, scope),
            effectId: channelAnimation.effectId === undefined ? undefined : math.eval(channelAnimation.effectId, scope),
            direction: channelAnimation.direction === undefined ? undefined : math.eval(channelAnimation.direction, scope),
            transition: channelAnimation.transition === undefined ? undefined : math.eval(channelAnimation.transition, scope),
        };
    }

private signalAnimationHelper(channelAnimation: ChannelAnimation, value: number): ChannelInfo {
        const scope = {
            signal: value
        };
        return {
            upHoldLevel: channelAnimation.upHoldLevel === undefined ? undefined : math.eval(channelAnimation.upHoldLevel, scope),
            downHoldLevel: channelAnimation.downHoldLevel === undefined ? undefined : math.eval(channelAnimation.downHoldLevel, scope),
            upMaximumLevel: channelAnimation.upMaximumLevel === undefined ? undefined : math.eval(channelAnimation.upMaximumLevel, scope),
            downMinimumLevel: channelAnimation.downMinimumLevel === undefined ? undefined : math.eval(channelAnimation.downMinimumLevel, scope),
            upHoldDelay: channelAnimation.upHoldDelay === undefined ? undefined : math.eval(channelAnimation.upHoldDelay, scope),
            downHoldDelay: channelAnimation.downHoldDelay === undefined ? undefined : math.eval(channelAnimation.downHoldDelay, scope),
            upIncrement: channelAnimation.upIncrement === undefined ? undefined : math.eval(channelAnimation.upIncrement, scope),
            downDecrement: channelAnimation.downDecrement === undefined ? undefined : math.eval(channelAnimation.downDecrement, scope),
            upIncrementDelay: channelAnimation.upIncrementDelay === undefined ? undefined : math.eval(channelAnimation.upIncrementDelay, scope),
            downDecrementDelay: channelAnimation.downDecrementDelay === undefined ? undefined : math.eval(channelAnimation.downDecrementDelay, scope),
            startDelay: channelAnimation.startDelay === undefined ? undefined : math.eval(channelAnimation.startDelay, scope),
            effectId: channelAnimation.effectId === undefined ? undefined : math.eval(channelAnimation.effectId, scope),
            direction: channelAnimation.direction === undefined ? undefined : math.eval(channelAnimation.direction, scope),
            transition: channelAnimation.transition === undefined ? undefined : math.eval(channelAnimation.transition, scope),
        };
    }