javascript - I cannot scale my font-size with D3 domain and range...? -

i looking scale book 'titles' in below dataset depending on number of 'weeks' have been on best-sellers list...so if book's 1st week on list, title appear in 18pt, , if book's 20th week on list (or maximum number week) title appear in 72pt.

e.g. of dataset:

        var hardcover_fiction = [             {                 title: "missing you",                 author: "harlan coben",                 rank: 1,                 last: 0,                 weeks: 1             },             {                 title: "raising steam",                 author: "terry pratchett",                 rank: 2,                 last: 0,                 weeks: 20             }         ]; 

e.g. of d3 code:

            .style("font-size", function(d) {                  return textscale(d.weeks) + "px";             })       var textscale = d3.scale.linear()                               .domain([1, d3.max(hardcover_fiction.weeks)]                               .range([18, 72]); 

i'm pretty stumped...any appreciated! :)

you're using d3.max incorrectly. first argument has array. second (optional) argument function extract relevant value each element in array.

the call d3.max(hardcover_fiction.weeks) returns 0 because hardcover_fiction.weeks doesn't exist. need

d3.max(hardcover_fiction, function(d){return d.weeks;}) 

the rest of code snippet should work expected.