How to use the angular-expressions.compile function in angular-expressions

if (!dvExpr) { return { names: [], evaluate: () => undefined }; }
  const match = grammar.match(dvExpr);
  if (match.failed()) {
    throw new Error(match.message);
  }
  const parsedExpr = semantics(match);
  const names: string[] = (parsedExpr.getNames() as string[])
    .map((name) => name
        .replace(/\?/g, '') // ignore elvis operator
        .split('.')
        // tslint:disable-next-line no-magic-numbers
        .slice(0, name.startsWith('$') ? 1 : 3) // $input or cliche.component.input
        .join('.')
    ); // drop object path
  const ngExpr: string = parsedExpr.toNgExpr();
  const evaluate: (scope: Object) => any = expressions.compile(ngExpr);

  return {
    names,
    evaluate,
    parsedExpr
  };
}

html('[ng-class], [data-ng-class]').each((i, el) => {
                  let cls = [];
                  let ngcl = html(el).attr('ng-class');
                  if (ngcl) {
                    ngcl = ngcl.replace('::','');
                    cls = cls.concat(
                      Object.keys(expressions.compile(ngcl)())
                    );
                  }
                  let datang = html(el).attr('data-ng-class');
                  if (datang) {
                    datang = datang.replace('::', '');
                    cls = cls.concat(
                      Object.keys(expressions.compile(datang)())
                    );
                  }
                  cls.forEach((cl) => {
                    html(el).addClass(cl);
                  });
                });
                return Promise.resolve();

html('[ng-class], [data-ng-class]').each((i, el) => {
                  let cls = [];
                  let ngcl = html(el).attr('ng-class');
                  if (ngcl) {
                    ngcl = ngcl.replace('::','');
                    cls = cls.concat(
                      Object.keys(expressions.compile(ngcl)())
                    );
                  }
                  let datang = html(el).attr('data-ng-class');
                  if (datang) {
                    datang = datang.replace('::', '');
                    cls = cls.concat(
                      Object.keys(expressions.compile(datang)())
                    );
                  }
                  cls.forEach((cl) => {
                    html(el).addClass(cl);
                  });
                });
                return Promise.resolve();

PowerTemplate.prototype.getValue = function (value) {
  var regexp = module.exports.BINDINGS_RE;
  var type = typeof value;
  var match = null;

  if (type === 'function') {
    return value;
  }
  else if ((type === 'string') && (match = value.match(regexp))) {
    return expressions.compile(match[ 1 ]);
  }
  else {
    return value;
  }
};

alertSchema.methods.validCondition = function(scope) {
    var expr = expressions.compile(this.condition);
    return expr(scope);
};